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Chevy Blazer GMC Jimmy Electrical Problems

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Comments

  • jlflemmonsjlflemmons Member Posts: 2,242
    Man, sorry to hear about your wife and brother. Seems the older we get, the more we realize our mortality. You and your family will be in my thoughts and prayers.

    regarding the switch, you're luck you are changing the cheap switch in the column. You don't even want to know what that multifunction switch on the left costs! Would you believe $195 wholesale???!!!

    And on a 2002 model, $265 wholesale!!! Needless to say, if anyone drives my Blazer and doesn't treat the switch with gentleness, I thwack them in the side of the head. :surprise:
  • cardoc50cardoc50 Member Posts: 49
    Thanks for the prayers.Prayer changes things. You seem like a very good man.
    Well,I had to change the multifunction switch over 2 years ago. Did'nt have any rear lamps. The 17 dollar switch I was reffering to was just the key switch.Come to find out the ignition switch directly under the key switch is 99.00.So I cleaned and tested the ignition switch and it is fine. I put the column back together and drove it for about an hour and everything seemed fine.I think I'll put license back on it and drive it again. My 99 cavalier is ok to drive but, it ain't no Jimmy! Thanks again for your help and concern. You are a good man. TTYL
  • jlflemmonsjlflemmons Member Posts: 2,242
    Let's see here...

    Cavalier, Blazer. Cavalier, Blazer....

    C'mon, that's not even close! :D
  • bitterbitter Member Posts: 22
    the ignition switch is considered that entire wire cluster that runs from the column to the fuse block! Looks good, no apparent damage or burns nor loose connections, it seems. Just bad engineering or something. My Brake and ABS lights would flash in the dash simultaneously as if it the computer was performing a systems check during operation, the blower would stop blowing and the windows would not roll down. Sometimes upon the initial start-up, there would be a 2 second delay b4 the dash lights appeared and the starter engaged. All caused by the faulty ignition switch (wire harness that connects to the key ignition unit and runs down to the fuse block located in the steering column)! 90 -100 bucks

    warren caine 97 blazer
  • cardoc50cardoc50 Member Posts: 49
    Yes you are right.After cleaning etc... I thought it was fine. Well it's not fine. On
    the initial(cold engine)start up,you crank the engine and it does not even try to
    fire. When you release the key,that couple of seconds that the engine is still turning from the attempt to start, it fires. After several attempts it will finally start
    on just those seconds that you release the key. After it starts(and it takes a while)
    everything is fine no dash lamps that should not be on or anything. Then you can turn it off and it starts like a new one all day.Unless it sets for a few hours4-8or so.
    I don't want to buy a 99.00 switch and it not rectify the problem. It is a 1997 JIMMY
    4.3HO with the OBDII injection.Plenty of fuel pressure and shows no trouble codes
    with my scanner or the Chevy dealership where my friend works. It runs smooth and no other problems.Your info is correct. Can you think of anything else it could be? I'm grasping for straws here. Thanks so much.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Ouch, what you are describing sounds like a worn out contact in the switch. An ohm meter could confirm this. I checked around on the S10-Forum site (interesting group, but a few knowlegeable folks there) and found this:

    Well, I went to the library and printed out the schematics of the truck. Everything under the hood was fine, like the fusible links. Then I probed the #4 fuse going to the dash idiot lights and only had 220mVDC. So I checked the ignition switch. Probed it and had +12VDC at the main red wire but still only 220mVDC with the key on. Then I used a jumper wire and wa-la. It worked. So I find an ignition switch harness at OReilly's for $90.00. The thing is you need a special E4 torx socket to get the igntion switch out. I drive all over town and finally find one for $6.00.

    I have another online source I am checking into. The guy above was having a very similar issue to yours. Someone else posted that if the vehicle can be started, gently move the key back and forth a small amount, and see if the engine shuts off, particularly when moving toward the "start" position. I will post more when I get an answer from these other guys.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Cardoc50,

    I checked my sources and they are saying most likely ignition switch. I hate pointing at something without more definitive "proof" but they also state that for whatever reason, '97 was a bad year for ignition switches in these beasties.

    Wish I could offer more suggestions, but that is all I can come up with.
  • cardoc50cardoc50 Member Posts: 49
    I agree with you. I'm going to remove my lower console today for another reason.
    I need to peel back my carpet to check the wiring that runs directly under the drivers feet.I don't expect to find anything wrong but,since I bought the Jimmy it had a small trans leak. One trans line is clean and has fluid dripping off of it. I can't get my hand up there to tighten the line up,so I may have to lower the trans just enough to tighten the line.I live in West Virginia and noticed the leak a few years ago in Daytona Beach Fla. Of course it has gotten worse over time. It looks like I may be able to acess the line from the top. If not,no harm no foul anyway.Of course if I lower the tranny a bit,I'll need to keep a good eye on the 4x4 switch and vacumn lines.I can do that from up top too. Maybe with a mirror but I think it'll be ok.
    I still think it's in the ignition switch but these are things that need looking into anyway. I've been driving it around some and boy, like I said a Cavalier ain't no Jimmy! LOL Thanks for the input. I may check voltage to the negative side of the coil when I crank it vs. when the key is on or running. Thanks friend for your input. I'll let everyone know what I find.(and then put an ignition switch in it) LOL
  • jlflemmonsjlflemmons Member Posts: 2,242
    While you are up to your elbows in that anyway, don't forget to check the oil cooler lines for leaks where the hose is connected to the metal part. This is the voice of experience speaking here. I kept thinking I had a leak above the cooler lines and one of the folks here let me know those lines will start leaking with age.

    how's your family?
  • cardoc50cardoc50 Member Posts: 49
    As I suspected there is no access to anything by removing the console.But hey,
    it needed a good cleaning under there anyway. Why did'nt I know that from being under the vehicle before? Again, does the word senile come in there somewhere?
    LOL. I was able to remove the crossmember and push the tranny over a few inches
    and tighten the line. when you take the x-member out, the transfer case rests on a
    non removeable x-member giving you an extra 3-4 inches. So that helped too. I put everything back together and guess what? The engine threw a rod through the side of the block! Just kidding.LOL. It started up fine every time I tried. It started up this morning cold and I started it a few more times.I did however tape up a couple places where it looked like wires were rubbing on the column and a plastic shield.who knowes?Everything is good right now.(knock on wood).I'll continue to drive it as much as I can(no tags)and see what happens.That's where we are at right now.I'll keep you posted. Thanks again friend!
  • jlflemmonsjlflemmons Member Posts: 2,242
    On the road, again ...

    Glad you found/fixed it. Of course, Murphy's law says wait till it rains and you're in your Sunday go to meeting clothes! :D
  • cardoc50cardoc50 Member Posts: 49
    Well, I told you wrong! I'm so embarrased. Another problem or maybe "THE" problem.How about the fuel filter bracket not bolted to the frame at the last change?
    Filter bouncing and vibrating wollowing out the plastic line and in turn causing it to suck air? Now also the rear metal line rubbing against the x-member of course another hole in metal line this time. I found the exact same vehicle at a local
    salvage yard. The owner gave me the lines and I cut off what I needed with a tubing cutter and attached them with compression couplings. Now all is well.I don't know why it started the other day.At least I knocked on wood(my head).First place to look huh? I going to sell it. I'm looking at the new Ford F-150 Raptor. It is a mean ride. Check it out. :mad:
  • jlflemmonsjlflemmons Member Posts: 2,242
    Ford Raptor I haven't looked at. I will go see.
  • cardoc50cardoc50 Member Posts: 49
    It will be available with 400HP. My son has a 2009 F150STX loaded and he said the
    Raptor will also be available with 500 Horses! And of course he will get one.My
    wife said NO! So I guess I'll get a little red car. LOL Who wears the britchess
    in my house? You're a nice fellow.It's been nice talking to you, and I hope we
    will stay in touch. I hav'nt seen anymore problems come up but mine. Talk to you
    later friend.
  • ryan502ryan502 Member Posts: 2
    Okay so none of my interior lights or the stereo work when the igntion is on and the car is running except for the eye ball lights, the mileage and gear indicator and the turn signal indicator lights (which are fully illuminated all the time but the signals still work.) This didnt seem to happen until a couple days ago when the temperature outside dropped to around 20 degrees. The stereo acts like it wants to work but cant until the ignition is off. Any help????
  • ryan502ryan502 Member Posts: 2
    actually figured out my own problem! the antenna cord where it plugs into the stereo has a metal band around it, a ground im assuming? anyways it was cracked in half so there was no contact. touched it together and everything popped on! just gotta get a new antenna adapter for my head unit. boo ya!
  • cardoc50cardoc50 Member Posts: 49
    I'm glad to see you fixed your own problem.Something so easy as a bad ground
    would be very very hard to diagnose. Other people should take note of this in case it may happen to them. I would not have guessed that the antanea ground would have caused your problem. I would have suggested a break in the circut insturment panel. I would have been wrong. Thank you for sharing the info with us. I will surely remember what you found for further referance.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Odd, indeed. The grounding band on the antenna lead does go to the body, and to the radio. But if the ground for the instrument lights and the other lights you mentioned is going through that ground, you might want to take a closer look under the dash for another missing/broken ground.

    The lighting circuit does go to the radio to give the dimming effect for the indicators. It also goes to the lights in the instrument cluster, but the turn signal indicators do not dim. Just sort of thinking out loud here, but all these lights should not be going through the antenna lead.

    Looking at a schematic on a 98 and later model. Shows a grounding junction with several black wires, one of which goes to the lighting circuit of the instrument cluster, and another that goes to the *stock* radio connector. This may be where you are losing your groud connection, and by connecting the ground through the antenna you are feeding back a ground through the radio lighting ground to the instrument panel. You might just look around the radio, and just to the left of the steering column (if I am remembering locations correctly) and see if you find a damaged junction/splice connector with black wires in it.

    A man can go crazy trying to track down the ground loops in a modern day auto electrical system! Good Luck!
  • ollie23ollie23 Member Posts: 1
    i have a 2001 blazer as i stop the brake pedal gets hard an pulsates back at me an the car keeps goin forward i let up it an reaply the brake an it stops. this happens at the end of the stop an there is a growling noice to the rotors are finr an i changed the booster. i had an asb lite on an when the lite went out this happened now the lite stays out an this happens every stop.
  • jlflemmonsjlflemmons Member Posts: 2,242
    You don't say how many miles are on the vehicle, but regardless, you have a problem in the ABS module. That vibration you feel is an engaged ABS, which will lengthen stops if activated under non-panic/hard stop conditions.

    When you first start the car, the ABS light should come on and a "buzz" should be heard from the ABS pump during this time. It is a diagnostic that runs every time you start the car. Don't mess around, get this one checked out.
  • cardoc50cardoc50 Member Posts: 49
    Remove your rear brake drums and inspect the brake lining. If you will notice, the
    rear brakes need adjusting. After you tighten your rear shoes, your problem will go away. It's an awful feeling when the brake pedal pulsates and that awful noise you
    are hearing. If you follow my instructions, I am sure your problem will go away.
    Try it and let us know what happens.
  • jlflemmonsjlflemmons Member Posts: 2,242
    I just re-read my post and there is an error in it. The "buzzing" sound from the ABS pump should occur when you first move the car after starting, not while you are sitting still.
  • retsdogretsdog Member Posts: 1
    I have a 97 Blazer and my daughter was driving it when it just shut down....All the dash lights are out and the truck won't turn over....I checked the fuses and found 5 or 6 that did not have 12 volts...ie eng, guages, turn signals etc.....the trans would not go into neutral either, I had to lift the dust boot off and manually release the shifter to get it into neutral....troubl shooting and moving things around the dash lights come up and I can start the trk...but turn the key off and try to restart,,,,no lights again....Help....
  • cardoc50cardoc50 Member Posts: 49
    Restdog, I am sure your altinator is bad. The same thing happened to me with my 1997 Grand Prix and olso my 1997 GMC Jimmy,which is the same as your Blazer.Go have the altinator tested at a auto parts store and you'll know for sure.
    Where I live a rebuilt altinator is $150 bucks.If it is the altinator, get a new one at the parts store. It costs a little bit more but you won't have to take it back 3 or 4 times like I did with rebuilds. It's the way these GM vehicles have been since the mid 90's. Good luck and let us know if that did'nt cure your problem :)
  • jlflemmonsjlflemmons Member Posts: 2,242
    This may also be related to a wiring problem that has been mentioned on these boards. Your description of mov"moving things around the dash lights come up and I can start the trk" makes me wonder. Seems like it was an ignition switch harness that several folks had problems with?
  • buster1155buster1155 Member Posts: 2
    I have a 1992 GMC Big Blazer that I can not figure out!!!! The wipers only work on high and short out board on low and do nothing on delay. I have just replaced the switch in colume and wiper motor for the 3rd time today. I have also went thru 5 seperate cir. boards all have shorted out in same spot. I have used volt meter and checked voltage to motor useing black wire that comes in to plug as ground. Any help PLEASE!!!!!! I am lost!! :sick:
  • edortizr6edortizr6 Member Posts: 10
    I think something is draining the battery. I replaced the battery and the alternator but that didn't help. I checked the fuses and they all look ok. I was thinking maybe it's the positive cable on the battery, but I'm not sure. I'm not familiar with the electrical system. I just tried to start the truck and there was power. As soon as I turned the key everything went dead. I'm going to get this battery charged again and take it from there. If anyone has any ideas, I'ld love to here it. Thanks in advance.
  • duntovduntov Member Posts: 133
    Parasitic drain can kill a battery in a few days or overnight, depending on how severe the drain is. Bad relays, the ECM, sensors, clock, alarm, and other electronic components can drain a battery if they are not in good working order. For example, I had to replace an older battery when it was compeletely dead overnight because the power door lock relay failed. I replaced the relay and the battery and the new battery seemed to maintain a charge. Just to check the state of charge, I purchased a Beltran 800 ma Battery Minder and attached the leads to the battery positive and negative terminals. I noticed the yellow charge light would come on for 20 minutes before the green full charge light was illuminated but I thought that was normal. My rear passenger side power window was slow at raising and lowering so I decided to replace the power window motor. Replacing the power window lift motor completely fixed the battery drain problem.

    Apparently the old power window lift motor was worn so bad that and was placing a small but continuous 5 or 10 ma drain (ground) on the battery even when the motor was not being used and the ignition key was turned off. After I replaced the power windlow lift motor and when I reattached the Beltran 800 ma Battery Minder to the battery terminals, the green full charge light is immediately lit, meaning the battery is at full charge every time I drive the car and turn the ignition key off. I can now leave the Battery Minder disconected for any length of time and when I reconnect it just to see what state of charge the battery is in, the green full charge light lights immediately, meaning the battery is maintaining a full charge while not in use amd does not need the Battery Minder to bring it up to full charge.

    That is my story, and it may be your problem, too. I have heard of some people pulling accesoory fuses until they find the accessory or accessories that may be causing the the battery drain. Before you start pulling fuses, get a $25 multimeter and see if there is a parasitic battery drain while the engine is not running.
  • duntovduntov Member Posts: 133
    Parasitic drain can kill a battery in a few days or overnight, depending on how severe the drain is. Bad relays, the ECM, sensors, clock, alarm, and other electronic components can drain a battery if they are not in good working order. For example, I had to replace an older battery when it was compeletely dead overnight because the power door lock relay failed. I replaced the relay and the battery and the new battery seemed to maintain a charge. Just to check the state of charge, I purchased a Beltran 800 ma Battery Minder and attached the leads to the battery positive and negative terminals. I noticed the yellow charge light would come on for 20 minutes before the green full charge light was illuminated but I thought that was normal. My rear passenger side power window was slow at raising and lowering so I decided to replace the power window motor. Replacing the power window lift motor completely fixed the battery drain problem.

    Apparently the old power window lift motor was worn so bad that it was placing a small but continuous drain (ground) on the battery even when the engine was not running and the accessory position of the ignition switch was not on. After I replaced the power windlow lift motor, I can reattached the Beltran 800 ma Battery Minder to the battery terminals and the green full charge light is immediately lit. That means the battery remains at full charge indefinately every time I drive my 1991 S10 Blazer 4x4 and turn the ignition key off. I can now leave the Battery Minder disconected for any length of time. When I reconnect the Battery Minder just to see what state of charge the battery is in, the green full charge light lights immediately, meaning the battery is maintaining a full charge while not in use amd does not need the Battery Minder to bring it up to full charge.

    That is my story, and it may be your problem, too. I have heard of some vehicle owners pulling accesoory fuses until they find the accessory or accessories that may be causing the the battery drain. Before you start pulling fuses, get a $25 multimeter and see if there is a excessive parasitic battery drain while the engine is not running.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Maybe this would help you?

    Testing for a Parasitic Drain

    This article is about a vehicle with dual batteries but it's all the same.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Be sure to check that the cables are clean and tight at the battery, and also be sure the ground cable is clean and tight on the other end, usually to the engine block. If you can find a digital voltmeter, check the battery with the engine off. If within 30 minutes the voltage drops more than one tenth of a volt, something is drawing more power than it should. For process of elimination, you can pull fuses and see what stops the voltage drop.

    If the car has power until you try to start it, and then all power is gone, double check all your connections to the battery and engine. Here again, a volt meter is invaluable. It will tell you if the battery still has power, but is not getting it to the vehicle, ie bad connection.

    Good luck!
  • cardoc50cardoc50 Member Posts: 49
    You definately have a short in the wiring somewhere between the fuse panel and the wiper motor assembly. You need a wiring diagram for your vehicle. You can buy a repair manual from your local parts store. In the back of the book you will
    find the diagrams.I wonder how you went through so many related parts and you never mentioned having a blown fuse.In the diagram you will find the routing of the
    wiper related wiring. Sometimes the wiring will go through other unrelated parts
    other than the one you have problems with. I suggest you get the diagram and start from the fuse panel.Sorry I can't pinpoint the exact problem but I hope you may
    use something I may have said to help you fix your problem. Good luck!
  • buster1155buster1155 Member Posts: 2
    Thanks, I went to dealer ship yesterday and got a print out or wiring harnness and pin pointed wiper wires #91, #92, #93. Talked to his service mgr. and tech went thru problem and steps taken. They were at a loss. I am on my way out to my shop to run the wires down one more time. The guys at dealer ship seem to think that the motor is not grounding and it is searchiing for a ground thru the circuit board. I have one more control board left and i am going to try it now with motor grounded to battery. About the fuse I do not understand that at all it has not blown I even changed thinking something was wrong with it and it has a 25 amp fuse installed. Rear wipers work fine and has a 25 amp in it also. :confuse:
  • cararyarbercararyarber Member Posts: 1
    Last night my nephew left the back gate on my blazer open all night. It started fine, but when I got to work this morning I tried to lock the doors and nothing..... I checked all the doors and made sure that they were all shut including the gate. Still nothing. Since it was the gate left open I tried to lock all the doors thru that lock. Which worked. So I thought. When I went to my blazer at lunch, all the doors were unlocked again. I checked the back gate, it too was unlocked. I got in the blazer and started down the road and I heard a click. Then the "gate ajar" light came on. Once I got stopped, I tried again to lock all the doors with no luck and the gate ajar light keeps coming on. What do I do?????
  • britmarie03britmarie03 Member Posts: 1
    I have a 98 Jimmy that Ive had for a year. 150k miles, runs like a champ...well since i fixed everything that was wrong. The last week or so, my trip odometer sporatically resets itself when I turn the car off, then restart it again. It always resets itself overnight (again this just started about a week ago), and sometimes resets throughout the day. I truly rely on my trip odometer for gas mileage as the gas guage is always jumping. I have very car knowledgeable friends and they have no clue. My best guess at this point is a short somewhere??? Any helpful tips, hints, or advice of where to start to try to get this fixed would be greatly appreciated!!!

    Thanks! :confuse:
  • slarraslarra Member Posts: 1
    I must be an idiot because I cannot find the underhood fuse/relay box on my 1997 GMC Jimmy SLE. There are posts on this forum that refer to it for that model year, and my Chiltons has a picture showing a big, black plastic box sitting atop the driver's side fender. But I don't see that on my Jimmy! Where should I be looking?
  • cardoc50cardoc50 Member Posts: 49
    I also have a 1997 GMC Jimmy SLE. There is no fuse or relay box under the hood
    of mine either. There is a big black box under the hood on the right side.It is your
    PCM (powertrain control module) or computer is what some call it. On the firewall
    behind the engine there are three relays.All three of these are for the airconditioner
    unit.The box on top of the left (drivers side) fender is the anti lock braking system.
    There are three relays behind the glove box. One is the fuel pump relay, one is
    for the headlamps for high and low beam and daytime running lamps. The other I
    can't remember just now. When you open the drivers door, on the side of the dash
    is where the fuse box is located. There are two relays in there also.So, no you are
    not an idiot.
  • cwangs1cwangs1 Member Posts: 4
    I was driving down the road today at about 70 with the cruise control on and the battery light came on, a very sort while after, the airbag light came on. I looked down and the volt meter was droping. At about 9 to 10 volts the gauges died. (All except oil press and the transmission indicator as well as milage.) A mile or two down the road the truck was slowing (loss of power) so I pulled over to the side of the road to squeeze as many miles out of it as I could. I hit the edge of the road at about 50 mph and everything came back to life. Cut the hunting trip short turned around and on the way home it did the same thing another 9 times for the next 30 miles to the house. There may have been some viabration when I pulled over hitting the rumble strips but I would hope that we don't jump on it and assume a bad ground right off the bat. Checked the battery under load reading 12.4v stuck the meter on it after starting the engine and was reading 14.06v then it would jump around abit to 9.05v, 10.0v, 12.4v then back up to 14.06v and hold steady. The battery is old but the alternator is 8 weeks old. I have been reading the posts and found some similar but not the same. I also have been dealing with the inaccurate fuel gauge for about 3 years. I fill the truck up indicates full, never gets below half a tank until it jumps to E. Fluctuates when shifting from P to D or R. Love this truck but don't trust it to take trips with any more. I have had it since new in 99. By the way it is an SLE 4x4 4.3L v6. Appreciate any input anyone might have. Thanks.
  • cardoc50cardoc50 Member Posts: 49
    The first and formost thing I think of after reading your problem on the Jimmy is you may have put a rebuilt alternator on it. I have a 1997 Jimmy and had to take my wife to a specialized hospital about 200 miles away. A week before we left,I had a
    bad experiance very simular to yours. After checking and letting the parts store check it, it was bad. When it started going bad, it would lose power and I had to
    pull off at several rest areas because the lamps were getting dim and the doors locked by themselves and a couple other wierd things happend also.I would sit in the rain and finally get someone to jump me.When it started the guage would go up to normal as it rapidly charged the battery. It happened a couple more times that night. Altinator was the first thing I thought of.As I said it checked bad. I bought a reman altinator saving a great deal of money. It was good until the trip home from the hospital,same thing. I will also mention our 99 grandprix gt did the same thing only we could'nt get the windows to work at all.We were stuck inside
    and I had put a reman on it too.Put a new(not remanufactured) one on both vehicles
    and that's been a few years back.My sons 99 camaro he put four remans on it before he finnaly listened and went to new. I don't know if you went for reman or new but,new ones go bad sometimes too. It shorted out the battery in my Jimmy also.Had to get a new one. Check or have your altinater checked first
  • cwangs1cwangs1 Member Posts: 4
    Thanks, thats what I initially thought too. I guess I will pull it and have it tested, it's not that hard to do. I have a couple minutes tonight and tomorrow night to do it.
  • jlflemmonsjlflemmons Member Posts: 2,242
    Follow on to what cardoc said above, you may have a battery plate (internal) that is coming apart. Will short, put a big load on the alternator, then when you hit the rumble strips, vibration knocks it free. Cheap easy way to know if this is happening is to feel the battery cables when you see the voltage drop on your meter. If those puppies are getting hot, the alternator is cranking amps, and the battery is sucking it down.

    All that being said, your "new" alternator may be having issues. Cruising on the road in daylight hours with the fan on low, you are not putting much stress on the alternator at all.

    By the way, that gas gauge problem you are seeing is a software issue with '99-'02 GM trucks. Instead of buffering the gas slosh in the tank with a baffle, the designers used software to "average" the signal coming from the sending unit to the BCM. Problem is, some code junkie only conditioned the signal when the vehicle is in drive, not reverse, or park. Want to see something cool? If you back out and the gauge drops and turns on the "low fuel" lamp, put the vehicle in drive and get moving up to about 20mph or so. Shift the tranny into neutral and put on the brakes. The fuel gauge will swing back up to the true reading. Before you stop, shift back to drive. This kicks the software back into "averaging" mode and the gauge will behave normally.

    You don't want to know how long it took me to figure out what was causing this! :D
  • dp2226dp2226 Member Posts: 28
    I have a 1999 Chevy Blazer, about 157,000 miles

    Like clockwork after 30 minutes, the abs will kick in under light pressure and the abs light will come on and stay on. After turning off the car for while it turns off then will repeat.

    Both the wheel hubs and sensors are new, the rear one is not but I cleaned them all just to double check. Did not see any issues with worn wires. The problem started months after I replaced the wheel hubs.

    I have only had the blazer since the spring and would notice the pedal would chatter a little when backing down my drive way which is a slight incline. Thought it was due to rear wheel bearings which I have not attempted to replace yet.

    Looking online found you can get the module rebuilt. Before I attempt to take this out was looking for other options.
  • cardoc50cardoc50 Member Posts: 49
    I can only tell you what I had to do. Tighten the rear shoes just enough to touch
    the drum. not drag or hold back. Bleed the entire brake system starting with the
    right rear (farest away) and work your way up to finish at left front. Try it then and see what you have. It should be ok. If not bleed the module. I do not know where you start there or the exact procedure. I may have it in some of my manuals but,
    you probably have one or have access to one. I know when your rear shoes need
    replaced or tightened That brake pedal and the noise the antilock module makes
    sounds like the blazer's falling apart. It's funny to me when mine has done it over
    the years.You don't need rear wheel bearings unless you see dark moist thick
    oil caked on the inside of the rear wheels.When a bearing goes out the seals
    warn you first.Just try the rear shoe adjusting and bleeding first and you will be
    surprised. That antilock brake system GM came out with is a joke.Every GM
    vehicle with that system should be recalled for a less complicated normal system.
    Sorry I said it's funny to me but I know how you feel. Good luck pal.
  • dp2226dp2226 Member Posts: 28
    Sounds good and I will give it a try. I did have a new master cylinder put on in the summer and rear calipers. Maybe there is some air left over or something.

    Does it matter if I have disc brakes vs drum brakes? I hate the aluminum calipers, stripped the bleeder on the first set just putting them on.

    Did your blazer do it after driving for almost the same amount of time?

    Thanks for the tip on the rear wheel bearings, back end sounded a little loud to me. The seals are definitely not leaking. Guess I am paranoid after finding out the first cause of a loud ride was the u-joints.
  • cardoc50cardoc50 Member Posts: 49
    I was'nt aware you had rear discs.As far as mine,like I said when the rear shoes got thin it would do it. Generally a car will go through 2-3 pairs of front pads to one set of rear shoes. Disc brakes really set themselves because as the pads get thin
    the piston in the caliper goes further and further out with no slack between the piston and brake pad. I like aluminum calipers on motorcycles and ATV;s but on
    a vehicle like ours,no way. I suggest you quickly crack the bleeders and close them
    immediatly(to see if they are going to loosen or strip)Now comes the fun.Bleed the system from rear to front. Oh yea, if your calipers are corroded,the piston may stick
    and the pads will chatter if they are just lying there unassisted and there goes your light and antilock noise.Check the calipers repair or replace as needed. Bleed the
    heck out of your brakes starting at the farthest away working forward.Your last one
    should be left(drivers side) front.I think you'll find this to work.If not,have your under
    hood antilock module checked.It has a printed curcuit board that can easily be replaced too.I would leave that one to someone else after getting bleeding instructions first. Good luck.P.S.Wanna buy a used Jimmy? LOL.I feel you'll get
    it this time around. Good luck pal.
  • dp2226dp2226 Member Posts: 28
    Definitely will give it a go. The front calipers are old so will check them out.

    I just popped the abs module out and unfortunately it is a Hayes 310 which according to a couple sites it cannot be rebuilt
  • cwangs1cwangs1 Member Posts: 4
    Thanks, I'll give that a try too. Sounds easy enough to fix. :)
  • dp2226dp2226 Member Posts: 28
    I posted this a while ago and was given some good tips but have not solved the problem. The front left caliper was bad so I replaced it but running into the same problem where the ABS light goes on after 30 minutes of driving

    It is a 1999 Chevy Blazer

    Both Wheel hubs with sensors new, calipers, rotors, and pads all the way around, master cylinder. The abs modulator is a Hayes 310, cannot be refurbished, no idea if it is good or not. I believe the brakes are properly bled. I also checked the wheel sensor connections to see if loose or dirty. I was only able to test the resistance which was 1 ohm each. I know there is a 3rd sensor on the drivetrain but have no idea if it is good.

    Before I drop $100 on an ABS Diagnostic tool, any other ideas?
  • daddyof_twinsdaddyof_twins Member Posts: 1
    have same exact problem with the fuse for the actuator fuse is fine till i drive the vehicle when idling it is fine can put it in and out of gear if you dont go thought it was actuator so found used actuator $140.00 still same problem
  • cardoc50cardoc50 Member Posts: 49
    On 4 wheel disc brakes with 4 wheel anti lock brakes,there is a sensor at all 4 wheels.If you haveRWALock system it only controls lock up of the rear wheels.If you have RWAL only the sensor should be in the tail shaft of the transfer case or if two Wdrive on the tail shaft of the transmission.I am assuming that you have a 4x4.
    If it's a RWAL system,the control unit(brain) is mounted at a different place but still easy to access. The wheel speed sensors and brake light switch sends info to thecontrol unit to monitor hydraulic line pressure to avoid wheel lockk up.It also constantly monitors the system to find faults in the system.When something goes wrong in the system, the"BRAKE" or :ANTILOCK" light will come on.A code will then be stored. The code reveals the problem.Now, getting the code of course requires a special scan tool. Some of the newer scanners will give abs trouble codes too If not you have to use one made for the abs system only. After getting the code(s) you'll have to use the tool to erase the code(s).That's the only way.Check all wireing connections,If you have different size tires and wheels other than factory,It WILL cause the Light to go on also.There can't be a 10 percent variance in
    speed sensors and tire size.That can be recallibrated with a scan tool.I don't know what is making your light(s) come on and without a scan tool, you may never know
    I was just shareing some info I knew about the system hoping it may help. Good luck sir,
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