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Chevy Blazer GMC Jimmy Electrical Problems



  • I have a 1995 GMC Jimmy. I have to contantly disconnect the positive terminal on the battery or it wont start in the morning. I have also noticed that while running the light for the daytime running lamps and the clock on the radio flicker.

    Does anyone have any idea what I should be looking at to stop this problem. It is getting to be a pain to have to disconnect the battery everytime I get home from work or leave my vehicle at work.

    If the battery is left connected I have to get the vehicle boasted.
  • duntovduntov Posts: 133
    edited April 2010
    You have excessive parasitic battery drain. All modern vehicles have some parasitic battery drain of about 10 ma which is normal. That is because of the sensors, clock, alarms, relays, acessories, etc. . If you have a shorted relay or damaged and shorted power supply wire, the battery drain can increase to the point it will completely drain the battery overnight and still will not blow a fuse. The only way I know how to isolate the battery drain , is to start pulling fuses while the engine is not running and watch a multimeter. Make sure all lights are off, such as the interior dome light or the glove compartment light. The cargo or dome interior light dimmer on the instrument panel can sometimes be in the "on" position and the operator will never realize it until the battery is dead. .

    Example: I had a shorted power door lock relay on my 1991 S10 Blazer and it drained my battery overnight. I installed a new fully charged battery and I discovered the shorted relay when I attempted to lock the doors after I installed the new battery. The doors would not lock so I replaced the power door lock relay. I probably did not need the new battery. I purchased a 800 ma Deltran Battery Tender and I keep in on my S10 Blazer if it will not be driven for more than a week.

    The charge light on the Deltran Battery Tender will indicate if you have a excessive parasistic battery drain. While the battery tender is connected to the battery, the indicator light will either indicate the battery is receiving a constant charge (yellow) to compensate for the excessive battery drain or it will indicate a green light to show a full state of charge. If the parasitic battery drain is excessive, the battery will never reach full state of charge and the battery tender indicator light will remain yellow. .
  • cardoc50cardoc50 Posts: 49
    phoenix,I had the same problem with my 1997 Jimmy.There are differences in
    wiring in about all models 1995 to 2004.Try pulling acc. fuse. It works my inside lamps and pwindows, locks,rear hatch.I think that is the right fuse. I would have the altenator checked first they are bad about shorting out. I had a short in the rear hatch wiring just above the headliner in the very back. There are several other
    possibilities. Try that then just pull a fuse at a time to get it narrowed down.Then
    you can go from there. I fixed one where the lower interior lights would'nt go out.
    The glove box, and lower foot lamps under the dash. Just start narrowing it down
    by the fuses and go from there. Good luck. :mad:
  • blazzzenblazzzen Posts: 1
    Hey just bought a 95 blazer 4x4 4.3 i replaced the Alternator when i start it up the gage inside shows over 14 when I use a turn signal it drops to 12 when the ac is turn on it also drops to 11-12 once it drop to 9 any ideas what i might be? it was doing this before thats why i thought it was the alternator any ideas would help thanks :confuse:
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,408
    edited May 2010
    I'm thinkin' bad battery or bad battery cables or bad engine-to-frame ground strap.


  • duntovduntov Posts: 133
    edited May 2010
    First you should check for dirty or loose connections. If your battery is known to be in good condition, you need to be certain both the battery cables are tight and clean and the alternator connections are also tight and clean.

    The voltage regulator Weather Pack connectior on the side of the alternator can somtimes loosen from vibration, or from blow back from the radiator cooling fan. Most often a loose Weather Pack connector was caused by being damaged or not connected properly after the alternator was replaced.. The alternator internal regulator connector is a GM Weather Pack connector that has a plastic locking tab. If the locking tab on the connector is bent from being removed incorrectly, the connector will loosen and that will indicate a voltage drop..
  • cardoc50cardoc50 Posts: 49
    edited May 2010
    It is normal for your Voltage guage to go to 14 when you start up your Blazer.These
    vehicles have quite an overnight drain on the battery due to all the options such as
    overhead console temp and compass and radio presets also the ECM runs check on certain circuits and sensors while the vehicle is not being used There is quite a drain and
    when it starts in the morning,the 100amp alternator immediatly delivers to the battery
    the power it needs to operate properly. You will see the guage drop as the battery
    needs less power to operate a system,such as brake lights and other things.Your
    alternator is fine(Ithink).If the guage falls a lot and your battery seems low,It is! You
    need to buy a battery that has the most cold cranking amps like a optima.I had to
    do the same thing. I paid around $150.00 for my battery and It has a eight year waranty(4year free replacement with no pro-rate)Sometimes these vehicles will have
    something pulling a lot of amps while it's sitting most are simple like a glove box light stuck on or something. Even if there is a interior lamp on, it should'nt run the battery down overnight.That's why these blazers and jimmys are required to have a
    real nice battery because of the electrical system.From 1995 to 2004,there are so many changes in the electrical system you would'nt believe it. I hope I made sense to you 'cause I did'nt make sense to myself. lol.but I'm speaking from years of experience on mine. before I would even start to fix it, I would gather all the info I could from manuals etc...and in this forum. Get your battery checked.It'll be ok. :)
  • duntovduntov Posts: 133
    edited May 2010
    It is a wise policy to have a 800 ma Deltran Waterproof Battery Tender attached to the battery if your vehicle is not going to be driven for a extended period of time. Two years ago, my 1991 S10 Blazer 4x4 had a shorted power door lock relay that drained my old Autolite battery overnight. I installed a new AC Delco battery and put a 800 ma Deltran battery tender on my Blazer every time I park it in the garage overnight in order to maintain the battery at a maximum charge. Maintaining a full charge will double the life of the battery.

    My Detran 800 battery tender will provide up a 800 ma charge until the battery is fully charged then it will stop the constant charge and will then maintain the battery at a full charge. . It takes about 10 minutes to acheve a full charge on the new AC Delco battery after I park the vehicle and connect the battery tender.. Normally, S10 Blazers through 1998, have up to 10 ma parasitic battery drain and that is enough to drain a weak battery overnght especially if the vehciles charging not working properly..
  • ok so it seems to me everyone is having the blinker problem. i just bought a 98 blazer and every time i close the door all the electicall stuff goes crazy. im talking the cd player 4 WD dash lites and so forth, but when i open the door everything works fine. what the H.. if you think you might have an answer for me please emial me @
  • tidestertidester Posts: 10,110
    please emial me @

    Let's keep the discussion here so everyone will benefit. :)

    tidester, host
    SUVs and Smart Shopper
  • my bad i didn't know that the emailed you when you recieved a new message. i dont really have alot of time on my hands to keep checking.
  • i just bought a 1997 blazer and i am having problems starting the truck, i have replaced the battery and but after it sat over night it still wont start, also when i try to accelerate the truck stalls out if givin to much gas
  • cardoc50cardoc50 Posts: 49
    edited June 2010
    By your starting problem you're not letting me know if you had to buy a battery because it would not crank,and after you bought one it would'nt start because the battery drained over night.I'll assume the battery is good unless specified otherwise.
    Had the fuel pump been replaced? If so there is a small emission hose on the top
    front of the tank that is almost impossible to see until it is too late. If it broke the connection to the tank,
    the vehicle will act excactly as you said. I can explain it if nessesary. My 97 Jimmy
    did the same thing and I have numurous accounts of the same problem. You may want to go ahead and change your fuel filter now too. When it won't start,remove
    the top off the throttle body and prime it with gasoline to see if it starts.If you would,
    I'd like you to try that and I can determine with quite accuracy what your problem is.You could post another text and we could go from there.Ask whoever you bought it from about any repairs such as fuel pump replacement or anything he has done to it lately. It's very important. These vehicles have to be (right on) to run like they are supposed to. I'll be looking for a new text from you. Get all the info you can about your Blazer. :sick:
  • linw1linw1 Posts: 1
    I have 2001 Jimmy with 43,000 miles; original owner. Past couple of weeks, the ABS and parking brake lights have stayed on a few times.
    Also, twice now, my hood has popped after I start the car.
    Once in awhile, if I put the driver's window down, it will not go back up right away.

    Could all these things be related to an electrical problem? I have had the car in for repairs the first couple of years I owned it due to different electrical problems.

    Any suggestions.
  • bitterbitter Posts: 22
    Hey, this is bitter! It sounds like your problem is your ignition switch. Not the key part, but rather the cluster of wires that that run from the steering column down to the fuse block. For some strange reason, they call that the "Ignition Switch." Cost about $90 @ Advance Auto. Not too difficult to replace. Some dash components have to come off, they say the steering wheel should be removed. I was able to replace mine without removing the steering wheel. The covers around the steering wheel most definitely have to be removed. The electronics are crap on these vehicles! It is not your relay switch! (located under the hood top part of the firewall, passenger side. The first unit- there are four or three little black boxes(relays) with attached wiring. Even though you can tap on this and things seem to momentarily work, NOT THE PROBLEM! IGNITION SWITCH! I was told by several techs erroneously that it was the relay switch! I even changed the brain. That just made the ABS & Brake light stay on rather than flash intermittently. Your blower motor should be acting crazy as well when all this is going on. The windows stop working, the blower motor comes on and off, the day runners stop coming on and there was a brief delay (about 2 seconds) after turning the key in the on position that the engine would turn over and the lights in the dash would light up! Changed the Ignition switch and all is good! Hope this helps.
  • bitterbitter Posts: 22
    Oh, and about that hood popping up....Make sure that your latch is lubricated real good with a lithium base oil. Oil it up real good and trip it manually with a screw driver a few times. Set it, pull the latch, set it, pull the latch etc.... Do this a few times. Make sure before you close the hood that the latch has been pulled and ready to receive the actual hood when you close it. It this doesn't do it, then you may have to adjust your hood latch to the proper position. Also, make sure that hood latch lever is completely seated back in the recoiled position. Pull it and then push it all the way back with your hand to the start position. Sometimes ( a lot of times ) the cable stretches and has to be replaced. This usually affect the opening of the hood, not so much the closing. (Usually)
  • bitterbitter Posts: 22
    That problem sounds like your fuel pump. It takes a significant amount of fuel pressure (PSI) to start the engine. Even though you can hear the fuel pump ramp up when the key is turned to the on position, it still may not be enough to open the injectors and emit enough fuel to start the engine. When going bad, sometimes it will and sometimes it wont. But when it does start, the hesitation at acceleration is because the fuel pump is not supplying the engine with enough fuel for higher rpm operation. It should shift funny to during this time too. That fuel pump cost close to $300. Have someone do a fuel pressure check on the vehicle. Both when the vehicle is running at idle and with the key just in the on position. I believe the gauge should read in between 44-60 psi at all times. Dont hold me to that one. If you can spray starting fluid down the throttle bottle (just a little) during the times It wont fire over, and it fires over after then. It is surely your fuel pump. GM is building a reputation for shabby electrical components. Their fuel pumps included! I hope they right the ship soon!

    Bitter bout my blazer
  • sandykvsandykv Posts: 1
    edited July 2010
    My Blazer battery runs down after a few hours. It is not the battery or alternator. Are there any relays besides one behind glove box and ones under hood on drivers side fender? I think there might be some under radio somewhere, because I can hear something click when starting and turning off blazer. Am I supposed to hear this clicking, and how do I get to it? Is there a good way to find out what is running battery down?
  • 1997 Jimmy all 4 windows stopped working when you push window button to go up or down dash lights (ABS and Ignition parking light) starts flashing and blower cuts out when you release button blower starts up??? Changed Switch on main door,very little power getting to switch. I removed remote starter thought it might be causing problem,Now i have more now key will not come out of ignition and airconditioning compressor clutch isn't working.also where is the ignition switch located?changed relays on firewall not sure if there is a relay for windows?? dealer said no but Haines book says there is. PLEASE HELP
  • kassismomkassismom Posts: 1
    i have a 2001 jimmy....i had to have the fuel pump changed last week and now it just stopped running and lost all power....was able to jump it to get it home and it died again,,,,charged the battery and it still wont start....
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