Are you a current or recent car shopper who bought an EV and then installed solar – or who had solar already, making the decision to go electric easier?
Are you a recent EV buyer (past 3 months) as a result of manufacturer incentives and dealer discounts on these vehicles, including year-end deals? Were you convinced to buy an EV after finding a good end-of-year deal, or due to uncertainty around which EVs will no longer qualify for full/partial EV tax credits in 2024? A national business reporter is interested in speaking with you. Please reach out to [email protected] by 12/15 if interested in sharing your story.

Blazer Jimmy 4WD Questions

wally1937wally1937 Member Posts: 1
I just had both front bearing assembies replaced and now the ABS brakes are activating on most every stop. What can be wrong ? Also; I pulled the fuse for the ABS brakes temporarily to avoid the ABS activating and when I pulled the ABS fuse the Cruise control quit working. There are separate fuses for the ABS and for the cruise. Will pulling the ABS fuse dis-able the cruise? Is it supposed to work that way?


  • johnnyd69johnnyd69 Member Posts: 4
    I have a 2003 2dr. Chevy Blazer and the 4wd just went for the third time (once a year for the past three years). Since I'm leasing it, it is being fixed free of charge, but my lease is running out in March and I have to decide whether or not to keep it (and won't if this is a chronic problem with the 4wd). Has anyone heard of this being a chronic problem (i.e. bad units being produced)?

  • guestguest Member Posts: 770
    All newer 4wd systems seem to have some quirks due to the move to shift on the fly smart systems. You never said what problems you had but if you read the posts most are small things that the owner can easily fix. Search other forums and see if your "next" vehicle has any problems. If not, then turn it in. The ZR 2dr was pretty good off road but not the best on road and the back seat is terrible so if any family now or planned dump it.
  • johnnyd69johnnyd69 Member Posts: 4
    Thanks! The problem I have had three times so far is: when I clicked the button to shift into 4WD from 2WD it made a grinding noise and then went dead (i.e. it was in 4WD high and I was unable to shift back into 2WD). Each time they've replaced the the unit and once the dashboard switch (although that has gone once as well). I was just wondering if anyone's heard of these 4WD units being defective. I love the truck otherwise and have not had one problem in 4 years other than this, but since I need the 4WD, if it is I'll dump it for something else.
  • repairdogrepairdog Member Posts: 948
    Which part the encoder motor? Is this a 3 button dash switch? Problem depends on case type and exact area and did a GM dealer work on it?
  • johnnyd69johnnyd69 Member Posts: 4
    It is a 3-button dash switch, and each time a GM dealer has worked on it; they've replaced the unit each time.
  • guestguest Member Posts: 770
    If they are just changing the dash switch thats why it keeps craping on you - there is a vac line to the transfer case 3 port switch that the encoder motor for 4HI directs vac to the front actuator and engages the front driveshaft. Sensors tell the TCCM (4wd computer) status and allows all to occur. 4Lo then has the encoder motor further engage the low gear. Someone isn't finishing the complete fix.
  • johnnyd69johnnyd69 Member Posts: 4
    Actually, they've replaced the switch as well as the transfer case (which is always the problem). When it's gone on me it has made a grinding noise and then it gets stuck in 4WD (as it is now). It seems to happen when it's cold; I live in the Northeast and need the 4WD for winter, so this is a huge problem. I'm just wondering if anyone has heard of this being a chronic problem, i.e. that the transfer case units are junk. I'm thinking they are, since this has happened to me 3 times in 4 years, two of them when I really needed the 4WD (in major snow storms). I'm thinking that it's time to let this car go at the end of lease and get something reliable.
  • watertankwatertank Member Posts: 2
    I had mine into the dealership (full extended warranty :)) last week. Thumped into 4hi on the fly and stuck. Got it back out in neutral only to have it stuck there. They changed the transfer case control module. Switched to 4hi once then tried on the morning I needed it. Tried in neutral moving, neutral still, in gear and both 4hi and 4lo lights would only blink at me. Then in the parking lot in neutral I tried again to go into 4hi and it thumped into 4lo. Ok enough of that.

    Back to the dealership. They called and said my battery wasn't good enough to engage the motor (my volt meter never wavered...seemed to hold a charge ok). I said go ahead and replace it. They called back and said there was another problem with the encoder motor.....they are in the process of replacing that now. Seems to me diagnostics would have shown that right away. I questioned the need for a new battery but not having tested it myself have to succumb.
  • repairdogrepairdog Member Posts: 948
    Yep, they were winging it. How much for that Delco battery - ask them to put the original back if that wasn't the problem or just pay it (only battery cost as that was NOT the problem you brought it in for and did not fix it - but you're a good guy so ....) As for a 2003 encoder motor if you are in a wet salt use state thats possible and that was free so ... sounds good if it now works.
  • watertankwatertank Member Posts: 2
    They just called and said with the new encoder motor, they still can't get it to go into 4hi (just 4lo). I gave them some info from here, wiring harness and vacuum line and they said that's where there going next. They also said the battery failed on the diagnostics........I'm on my way over to get a loaner. Thanks for the forum and the info. Will keep you posted.
  • repairdogrepairdog Member Posts: 948
    I looked back and never saw if this was a 3 or 4 button dash switch - 4 is Autotrac case. If it went into 4Lo then the front axle coupler worked. 3 button np233 case the encoder steps once to 4HI and sends vac to front actuator via a 3 port vac switch on the case and engages the front drive shaft. Steps again for 4Lo.

    Autotrac np 236 case is different and front driveshaft always on. For 4Hi you have a firewall solenoid that the TCCM energizes to supply vac to the front actuator and the encoder only steps for 4LO.

    Would look at TCCM,dash switch, 3port or firewall solenoid (by type) or a cut wire/loose connector. First I hope they tried to reset the TCCM by removing power for 30 minutes.
  • ericsf71ericsf71 Member Posts: 1
    I'm sure this topic has been discussed on the boards before, but I could not find anything about it. I have a 2001 Chevy Blazer that I've never had a problem with until recently. In the past snowstorm I put it into 4 wheel drive (3 buttons on dashboard) and everything was fine. But when I tried to put it back into 2, it would only blink a few times but go back into 4hi. After turning the car off and back on it eventually went back into 2wd. Now when I try to put it into 4wd, low or hi, I can't. The buttons don't blink, I don't hear any noises or anything. The only way i get anything out of the buttons is if i put it into neutral, in which 4hi and low will blink 2 times but then remain in 2wd. Any ideas on what the problem could be? Could i fix it myself or do i have to take it to a dealer and how much could it cost to fix?
  • 2004blazer2004blazer Member Posts: 2
    Sounds like the same problem I am having with my 2004 Blazer. It will go into 2 hi and 4 low the lights will blink but WILL NOT go into 4 hi. Chevy dealership stated that I had to put it on the computer to find out what the exact problem is. ANYBODY KNOW WHAT IT IS AND HOW I CAN FIX IT WITHOUT SPENDING A FORTUNE ?
  • 2004blazer2004blazer Member Posts: 2
    Sounds like the same problem I am having with my 2004 Blazer. It will go into 2 hi and 4 low the lights will blink but WILL NOT go into 4 hi. Chevy dealership stated that I had to put it on the computer to find out what the exact problem is. ANYBODY KNOW WHAT IT IS AND HOW I CAN FIX IT WITHOUT SPENDING A FORTUNE ?
  • repairdogrepairdog Member Posts: 948
    Check the vac lines under hood and to the reserior drivers side fender. Then 3 port vac switch on transfer case. Then encoder motor must steps once for 4Hi and 2nd time for 4Lo. Then TCCM computer must see all sensors response good. Pull battery power for 30 min and see if TCCM resets. There are many posts on all these found with a search.
  • sandman7sandman7 Member Posts: 3
    93 chevy s10 Blazer 4wd hi lo switch not working checked accumulator fine replaced 3way ball switch on TC. I can get my 4wd switch to work fine as long as the truck is in neutral it will go into 4wd low-high and back to 2wd. Didnt realize it would work in neutral until after working on truck i realized i was stuck in 4wd high but the light on dash didn't indicate anything got to trying anything to get it out and discovered it worked in neutral. Any advice?
  • repairdogrepairdog Member Posts: 948
    N is the only position you can go to 4 Lo in - always was. As for 4Hi the encoder motor probably has rust or crap on it and is hanging up - remove and inspect/replace as necessary. Th edash switch sends a voltage to the TCCM to tell it what to be in and if the lights out thats probably bad or connector to the TCCM dirty. Believe on yours its behind the center console/ashtray area.
  • cnm50cnm50 Member Posts: 1
    I have an 03 trailblazer. The 4 WD light will switch to 4hi &awd.The light will stay on like it should. You can hear it actuate. It will sometimes make a grinding noise and you can hear it grind into gear. once it is in gear it seems to work fine. It seems the only way to get it in 4WD is to stop, switch it into 4WD then creep forward untill you can hear the gears mesh.
  • repairdogrepairdog Member Posts: 948
    I'd look at the vac to the front axle actuator and make sure the line is good - sounds like a partial vac so the front axle coupler is slowly engaging.
  • kenagirlkenagirl Member Posts: 4
    I recently replaced the baring/hub assembly on the driver's front side of my 98 Chevy Blazer. I also replaced the front tires, as they were bigger than the back tires. Truck drove great and 4WD worked like a charm through the last couple of snow storms. However, just a couple of days later, the alignment is off, the steering wheel sits crooked to make the vehicle drive straight and the steering feels very loose. Do you think this is due to 4WD use? What should I check for? Highway driving has become a bit scary. I would appreciate any advise you may have to offer. My regular mechanic has retired and closed shop and I'm at a bit of a loss now. Much appreciated as always.
    Kenagirl. :confuse:
  • repairdogrepairdog Member Posts: 948
    Have an alignment shop check the front end out. My guess is worn steering components such as the lower ball joints, tie rods, or idle arm and the shop can pinpoint for you - estimates are always free. This assumes the hub replaced was correctly bolted in and all items tightened and that the other hub is OK.
  • scoop2scoop2 Member Posts: 2
    I have a grinding noise in two wheel drive and when i put in 4 hi it stops i had at a shop and when they took it out for a test drive it was good after i took it home it never made a sound.I used it for a week driving around no noise,i used 4 hi and went back to 2 hi was ok and then all of a sudden it started to made a grinding noise but it seem to be coming from the right hand side,it seem to shift from 2 hito 4hi with no problem the only thing when making sharp turn 2 hi is seem to be jerky
  • repairdogrepairdog Member Posts: 948
    Would have to point to the front axle coupler partially engaging due to a leaking vac solenoid located on the firewall. Follow that vac line from the drivers side and you will see the solenoid. Pull that line, plug it with a golf T or something and see if that fixes the noise. If so simply unclip that solenoid and get a new one at the dealer - you need the part or # to help them about $30.
    If thats not it check the front diff fluid and transfer case fluid.
  • scoop2scoop2 Member Posts: 2
    i have 2001 blazer that realy hard on fuel it gets about 13to15 miles to the gallon i phoned gm and they said they can't do anything and they are a little hard on fuel so is there any reason i can't put a fuel mizer cam in it and if so what do i have to do to the computer thanks
  • repairdogrepairdog Member Posts: 948
    Wrong approach. Depending on gearing (3.42 vs 3.73) and how you drive you have a problem that is simple maintenence. My 99 4wd gets 20mpg avg with the lower 3.73 gears if I drive normally, but if cranked up to 80 over 2500rpm constant down to 18, add AC on down to 16. Slow her down to 70 and mpg go up. Other 4wds with the 3.42 I have get same but alittle better at highway as rpms lower. If you have 2wd then should be better by 1-2 mpg also.

    So, tune it up - cap/rotor/plugs/wires/air filter and clean the MAF sensor in the intake (if you use a K&N oiled filter that is common problem as owners over oil and get sucked onto sensor and milegae drops). Any brakes dragging (like the rears if a recent brake job that did not replace the rear calipers). Something easy is wrong.
  • repairdogrepairdog Member Posts: 948
    ABS sensors are contained in the new hubs so whoever installed them probably ripped one of the senor wires or didn't plug the connector in all the way - get them to fix it. Without looking at the wiring diagram I'd say the ABS (brakes) has to be working due to the cruise is kicked off by the brake being applied so computer assumes brake on or problems so deactivates the cruise.
  • hangwaiterhangwaiter Member Posts: 1
    most automatic vehicles tend to move(in DRIVE) immediately once you release the brake.
    However, my 2001 blazer just stands still even when the engine is cold (and idles faster). On pushing the accelerator slowly, the engine revs up to 1500 - 1600 rpm and only then +- half a second later you feel the torque convertrer doing its job and the car starts moving.
    does this indicate a problem or is it normal for blazers?
  • repairdogrepairdog Member Posts: 948
    This is a problem. Should go immediately, unless the rear calipers are locking up or if pulling a heavy trailer. Check the trans fluid level and fill if required - engine idling and note the hot and cold lines on the stick. If full get the filter changed next.
  • acarlsonacarlson Member Posts: 1
    Ok, I'm sure that people have posted this before, I've seen some of them. My 99' Blazer is stuck in 4Lo, I made sure it was nuetral, I checked all the vacuum hoses and I disconnected the battery in hopes that it would reset the computer but thus far it's still stuck in 4Lo. I am trying to see what else I can to try and fix it before I decide to take it to a mechanic. So if theres anyone who has any suggestions please let me know.
  • repairdogrepairdog Member Posts: 948
    Put the vac source line to the front axle (drivers side under hood) and see if it drops out when you push 2wd. As the many posts have talked about you have vac, transfer case encoder motor, that TCCM or computer in the pass isde kick panel (put the conncetor and make sure its clean and tight), and the front actuator.
  • thesweetrosslgthesweetrosslg Member Posts: 28
    i can push the button in my 97 Jimmy and i can hear a and feel it shift into 4 wheel drive and then when i hit 2 wd button i hear it and feel it shift back but its not working when i look are it if i get stuck the 4 wd dose not engage but the buttons light up and i can hear the noise what coudl this problem be and im not able to fix it myself how mouch could the most a shop would charge me cost do you think
    thank you
  • repairdogrepairdog Member Posts: 948
    Search in the forum for many posts on this.
    Basics is you have to go thru the vac system and 3 port vac switch on the transfer case, the encoder motor on the case, the vac actuator under the battery, the front axle coupler, and the TCCM (4wd PC) to resolve. Vac lines and 3 port switch are where to start - see if all good and not rotted/split.
  • grose67grose67 Member Posts: 5
    I had the type of issue happen on my 95 Blazer. What I found was a kink in the vacum line. Once that was fixed, the 4 wheel drive worked great and has ever since. That was two years ago.
  • gregg67gregg67 Member Posts: 1
    i have a 2001 blazer that is stuck in wheel says its in 2 wheel.i'm pretty sure its HI you can hear it switch to LO and feel the difference.any ideas and how to chek servo's,switches etc; would be greatly appreciated.
  • aaronj8aaronj8 Member Posts: 1
    my blazer is stuck in 4WD Hi. Everything worked just fine until I put in a new heater core (what a job that was!) The heat works great now, however, upon starting it back up it is now stuck in 4WD Hi. When I try to switch to 2 Hi, I can hear it trying, but it isn't switching over. Any ideas on where to start? I know it is electrical in nature... i'm thinking that i just bumped a wire some place when i was in the dash, but don't know where. Any help would be GREATLY appreciated!
  • thumpingonethumpingone Member Posts: 2
    I have a 98 Blazer I bought a few months ago... I have been getting very frusterated trying to figure out this problem.

    The truck feels like I'm towing a trailer all the time, however the odd time it seems to lighten up. All the bumps on the road are very hard, very rough ride and when I go over bumps it bounces all over. Now when I put it in 4WD and hit the gas, I hear a cluck from the front left wheel. It almost sounds like a CV joint on a FWD car. But louder and harder.

    I feel like these problems are all related to the same thing, but I can't find it. I've checked if any of the brakes are draging there all good. It possibly needs an alignment. If anyone can help, please do before I sell this thing!

  • posblazerposblazer Member Posts: 2
    Push button to 4hi, it blinks for a few seconds and goes back to 2hi same when trying to put in Auto 4wd, any help would be appreciated.
  • beyondtime024beyondtime024 Member Posts: 5
    Don't know if it helps, but I just had the same problem except none of the lights were on!! I took the dash completely out to find out it was a wire had broke going into the harness!!! I just snipped the other side and now it works fine!!! I also had a couple wires that were pulled out of the harness just far enough that my fuel gauge and my temp gauge would not work so i just took a screwdriver and pushed the wires in just a ittle to were they were working!!! Hope this helps!!!
  • mcassel4mcassel4 Member Posts: 3
    Can you here transfer case motor trying to shift, if so then it could be inside the case its self, this is the problem I have now. I can here the motor trying to shift into 4Hi but it would not go, $200 new motor and it still would not shift. I found you should be able to remove case shift motor and you can shift it with a wench with little effort,if all is in good working order in my case it dose not! So i will be removing that part next.the button tells your 4wd controller what you want it check to see if the motor dose what it is told if it dose not move it tells you that nothing is happing.the hole thing is a pain in the...., when it don't work.
  • roper77roper77 Member Posts: 1
    4X4 stuck in 4L, constant ticking under pass side dash, replaced 4X4 switch on dash, disconnect batt, still doing same, starts ticking appx 30 secs after key is on. Any ideas, please help.
  • mcassel4mcassel4 Member Posts: 3
    Need to know if you can here, transfer case motor trying to shift ,you should here a noise right under the center console . there is a drive motor that is turned on by the dash switch, the clicking you here on the passenger side is a relay that powers the motor. I think if you can here the clicking that the dash switch is not the problem. if the relay is good then you should get power to motor on the t.c. I found the motor to the T.C. was not that hard to change About a 40 min job. remove front driveshaft {4 bolts}.then you unplug motor and it comes off with [3 bolts]. Then you take that to local auto parts to match , because there is three different motors and nobody witch one you have. with motor off you can shift T.C. with a wrench, there is four positions 2hi 4hi N 4l you will have to shift to 2hi to install new motor, if you cant shift you can try to move rear wheels to line up gears, or you could have T.C. internal damage.hope this helps.M.C.
  • posblazerposblazer Member Posts: 2
    Thanks and yes motor is working I actually found the problem and fixed it a few minutes ago. I started with the actuator under the battery (actuator was in good shape) checked all the vacuum line going to vacuum switch under hood seal (those were also in good shape). Then I had a friend hold the elec. switch on the front differential pulled out the switch tried to put in 4 wheel same thing it just blinked compressed the ball on the switch and the light stayed lit so we went back to see if the actuator was actually moving and no so we went back to vacuum switch under the hood seal ordered the part from GM (they call it a valve) put the part in and it worked. $50.00 for that I brought back the actuator which I didn't need that was $59.00. Hope this helps you or anyone else.
  • jeremys26jeremys26 Member Posts: 2
    have 2003 blazer 4x4, no major problems, except bad gas mileage, was driving on ice decided to switch into 4 wheel drive hi, pushed button, it is 4x4 on the fly right? running 35 mph, pushed 4x4, got funny grinding sound, acted like didnt want to go anywhere, grinding, loud.. under blazer, so when heard the sound, pushed in rear wheel 2x4 and still had sound, slowed down to 15 mph, and pushed in 4x4 low, still had the grinding sound, then pushed in normal rear wheel drive, and must have hit a bump but felt a tug of the vehicle and a loud bang, and then it started driving fine again, needless to say, wondering why it happened and what it might have been, haven't used 4x4 since...could it have been frozen?, it was 15 degrees that day..took it in about 4 months ago to jiffy lube and they changed the rear differential fluid...could it have been something they did? thank you in advance
  • mcassel4mcassel4 Member Posts: 3
    you should try the 4x4 again , well in park,it should shift,and not grind because your not moving, if it dose shift, then try to drive if you here noise than you got trouble. The rear differential drive all the time two or four wheel drive, so if it was in that area you would have know it long before now. you could have lost your front drive shaft or you have problem in you transfer case.hope this helps.
  • charlie_acharlie_a Member Posts: 2
    ok my 95 Blazer LT has 4WD but when i push the button on
    the dash for 4WD it lights up but it dont feel like its in 4WD
    and its not. What may be wrong and how would i fix it? im
    thinking maybe the vaccume sensor may be bad...

    Also i would like to raise it up a bit but since the leaf springs
    are under the axle its more dificult. all i need is some
    sugestions on the cheeper better stuff to get to get the
    height up the most.

    Charlie Armstrong
  • charlie_acharlie_a Member Posts: 2
    ok well i checked the vacume lines and one was bad...
    fixed that and it still dont work any other sugestions

  • arvadaarvada Member Posts: 2
    This is my daughters 97 Jimmy v6 auto. The 2wd button does not light, the 4wd buttons do. I hear the clicking under the dash. 4wd will not engage, but when I try to go to 2wd I hear the right front grinding. It recently had the heater core replaced. I removed the battery connection for 30 minutes, turned on/off 5 times. No changes. the plug on the back of the dash switch seems tight but I reseated it anyway.

    Any help nailing this down is appreciated since I have the flu and don't have much energy to trouble shoot every single point if I don't have to.
  • arvadaarvada Member Posts: 2
    Small update. I have since pulled the TCCM plug and cleaned with WD40, pulled the battery/tray and the vacuum module under the tray doesn't have any broken lines to it. I'm not sure what to do with the battery in order to test it while the engine is running. I followed the vacuum lines to the area of the distributor/trans dipstick tube. I could see where it went down to. I did find one vacuum line by the power brake unit plugged with a screw. I attached it to the round black vacuum bottle on the hood. No changes. I may take it to a shop tomorrow since I didn't want to get under it today (cold, wet). Any additional ideas welcome. Thanks.
  • chewy77chewy77 Member Posts: 2
    Shifted into 4hi yesterday morning. Felt the 4WD engage. Immediately after, all of yellow 4wd indicator lights on the 4wd push buttons shut off. After driving for about 2 minutes the light on the 4hi button came back on. Now it is stuck in 4hi. I have pushed the 2hi button multiple times and nothing happens. Any idea what the problem could be? Any help would be greatly appreciated. Thanks.
  • maurerush2112maurerush2112 Member Posts: 9
    i recently received a 95 blazer for my daughter. it needed a little here and there, but in decent shape for age and miles(265,115) and obviously the 4wd didn't work. I have been trying to be a good mechanic all my life 30+ yrs. feel i know quite a bit, but as any good mechanic would say, not everything. i am always open to listening, and reading,etc. I knew coming to this forum area I would be helped by reading complaints that are consistent to mine. i must give an open thank you to everyone who participates in these forums. a mechanic knows that you can't keep up on every model or every problem, and i've worked on my share of blazers/s- trucks, but not everyday. so reading the posts here refreshed my memory on the what, where, hows, etc. for those who are searching for the cure of no 4wd, my solution was completely checking all electrical connections, all vacuum hoses including the 3 port switch on the transfer case underneath. take the time to check it. the three hoses eventually route up over the top of the transmission and are assumed to be protected from the elements, but one of them i found was bad. also one at the actuator was cracked. also all from purge canister (black ball drivers side). also do not overlook the main line from purge goes to a main port on backside of intake just left of distributor. that one is hard to see, but if its disconnected you will not have 4wd.
    all my babbling comes to this...
    i got this truck from a relative. was told the 4wd never worked, and they had it for approx. 9 yrs. i took a couple hours of my time, traced every possible vac line, elec. connector, got dirty,
    but my daughter has a 4wd that actually has 4wd.
    my complaints were consistent with everyone elses
    but by taking the time to read everything i could find here, it helped me cut hours and possibly dollars off the whole project.
    as an old timer once told me, "If you don't learn something new everyday, your not paying attention in life" :shades:
Sign In or Register to comment.