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Chevy S10 - GMC S15 and Sonoma Electrical Problems



  • Sounds like it might be a bad ground somewhere. Look for the small ground wires that lead to the fenders from the negative post on the battery. The things you mentioned I do not think are on the same circut and fused together. Also look and make sure the firewall is grounded inside the cab. Going by my memory, I think there is also a ground strap on the engine side firewall also on the passenger side.
  • Thanks,

    Will try it asap!!!!
  • The Sonoma sage continues. Today I got a chance to get back into the electrical problem. I took apart the dashboard and did not see anything obviously wrong with the grounds I could see.

    Then I thought, lets check the fuses again. I looked at the big fuses this time and the 50 amp fuse on the IGN2 circuit had blown. Alright! Now we are getting somewhere. I took the smaller fuses out of the HVAC and turned the key to the ACC position. Everything worked (wipers, radio, odometer, ect) like a charm. I turned the key to the ignition on position and I could hear the fuse pop. I pulled the fuses for the radio and even pulled the radio out, in case someone had done something to it and the fuse blew when the key was moved to the run position.

    I know I have a short somewhere, but have no idea on where to start. As I said, I saw nothing obvious under the dash. Would pulling all the HVAC fuses also kill the power to the heater blower? The AC was turned off so I don't think that was a problem.

    Any ideas on where to start looking again,

    Thanks for the help!


  • I have a 98 sonoma with 120k on it. I have been having a problem for a while now. I will be driving down the road and all my dash light will come on and the gauges go crazy and the truck just dies. most times i can turn the ignition off and then it will restart. any ideas?
  • Had very similar problem with my truck when new less than 3000 miles on truck same thing just dies. Had dealer replace wiring harness now have 235,000 miles on truck have not had the problem again.
  • While investigating a problem ( intermittant at first, now won't start/turn over ) I found that one of the three Ground/Negative leads on the battery was going nowhere... It wasn't connected! [ Probably the result of shoddy workmanship at the Body Shop during some front-end repair work. :-( ] So: Where should the Black w/White tracer lead go to? Since it was working fine before, even with the mystery wire not connected, what else should I be looking for? Battery Voltage/Charge seems OK, Starter relay on the Fuse Block 'clicks'. But I don't seem to hear anything from the Starter Solinoid... Thanks in advance.
  • That ground goes to the fender. As for checking the no crank situation: Sounds like the relay is being switched by your ignition switch. Verify power on the small wire of the starter solinoid with a test light or volt meter as the key is turned. Should have about 12v, On the large battery positive cable at the starter verify the voltage doesn't drop below 10v when you attempt to start. You probably have a bad starter, bad battery, or bad grounding to the engine. Don't assume your battery is good because of voltage. It is the amps that start the vehicle. Load test the battery. Without proper tools, turn your headlights, wipers, and heater blower motor on and see if the battery voltage drops below 9.6 volts, within a 4 to 5 second period. If it does, bad battery, or loose or dirty conections at the post.
  • Ok, Got it figured out finally. The ignition switch was shorting out somehow. A quick change out of the switch fix the problem.

    Thanks for all the advice!!!


  • I have a 1998 gmc sonoma and i have the option to override the dome lights in my truck but my dome lights will not turn on or work period. When the door is opened or when I turn the switch to turn them on, they do not work...What could be the problem? I have checked the fuse and it is completely fine for the inside lights but other than that I am at a complete loss. I also am wondering why my 4 wheel drive light that indicates whether my truck is in normal or 4x4 is also not functioning. Anyone able to help?? It is much appreciated!!!
  • marc38marc38 Posts: 1
    2002 GMC Sonoma. No foglamps installed. Good taillight bulbs. New headlight switch. Voltage at taillight connector. Ran a jumper wire from battery to taillight and it would not light. Grounded with no change. All other lights work fine except license plate lights. Fuses have all been checked. Relays are fine. Finally have installed my own taillights on the rear bumper, but I'd like to fix the original ones. Anyone have any ideas?
  • my flex fuel sensor has an error. so i figured its either the sensor that has went bad but i checked the voltages from the wiring harness and they are not what they are supposed to be. anyone know where the wiring harness is routed or how i can trace the problem. thanks
  • I have a 93 sonoma with the 4.3L and 4WD. recently I have been having some electrical issues. A few days ago I was driving and the engine just died. I let it sit for a few moments and it would start back up. The next morning i needed a jump to get it going. So i thought it was the alternator, took it in and had it tested 3 times. Passed all 3. The guy at the autoparts store said to check all the grounds, which i did, and even replaced the negative batery cable. now the voltage will fluctuate from about 10 to 16 volts. To make the issue more confusing, 1st gear on the transmision has never worked like it is supposed to. but now... when the voltage is high like it should be, the transmission shifts smoothly and 1st gear has all the horsepower you would expect. but as im driving the voltage will drop and bye bye 1st. Any ideas on what i can do to fix the electrical??
  • I have just recently purchased this truck that had a motor swap with another 2.2 liter and after the swap they didnt strap the positive cable down and it burnt up , they replaced the wire and it ran fine drove it for a week and then it died now the truck turns over fine just wont start , so i replaced the fuel pump and still nothing ,so then i hooked my snap-on scanner to it no codes but i noticed on battery voltage with the key on only reads 5.0 volts and theres 12.0 at the battery i checked the grounds but maybe im missing something any suggestions?
  • When the cab is warmed up the meter is fine, I had alternator replaced 2 times, new battery, Check cables at battery and on starter.While cold and rev eng,lights go dim then meter drops I am going insane with this problem. I am wondering if the instrument cluster is bad since cold contracts and warm expands, Maybe volt meter gauge itself , maybe the starter? Any suggestions would be appreicated. One person told me a ground problem. If a ground problem wouldn't it do it all the time? Thanks in advance :confuse:
  • cwildcwild Posts: 2
    My 2.2 S-10 started having issues starting, at first I took the starter out and since it was o.e.m with150000miles. replaced with brand new (not rebuilt). Still had the same problem so I traced all the wiring where it went, tested the relay by swapping with headlight relay, and everything looks good. Took the plastic cover off pos. terminal and cleaned all corrosion off. Yet I'm still having the same problem. The starter kicks the bendix out when I turn the key and just spins, it wont turn the engine over. I have been informed by Napa that there isn't a shim pack for this model year. does anyone have any ideas.
  • cwildcwild Posts: 2
    Just wanted to update found the problem in case anyone else runs into this. The flywheel is not connected any more don't know if bolts are broken or vibrated out. will update later. Found this by pulling inspection plate and watching as someone else turned key. Saw flywheel spin but didn't turn engine. had helper stop and was able to spin flywheel with fingers.
  • gonogogonogo Posts: 879
    My flywheel broke near the C/S under warranty, they installed the transmission wrong at the factory. There was even a service bulletin on it.It broke at 10 K.
  • Hi!
    Check for the ground connection, it's a tab between the motor mount bolt and the motor case, it could be broken !
    I had that problem ...

    Hope it'll help !!

  • On my 93 Jimmy, used during winter only, everything was ok went I park it last summer but now the wipers start but do not stop and my windshield washer doesn't work !!!

    Is anybody got that problem ?
    Any help would be appreciated !

  • ted42ted42 Posts: 2
    I'm wondering if you got a solution to your problem because mine does the same thing. Please reply!
  • Hi Ted42,
    My problem was the wiper-motor itself, I open the motor case and the parkswitch was stuck, tried to fix but broked the plastic lever acting that switch, so i replaced the motor assy and everything is ok now .

    Hope it'll help you !!
  • ted42ted42 Posts: 2
    Hey, thanks a lot! I noticed my wiper blades don't work always. I will try this. :)
  • 2000 S-10... I have no lights on the 4 wheel drive switch, the indicator for the transmission and the odometer will not light up. It has been very cold and snow here... Any ideas? :confuse:
  • Same truck, same year, no lights on the 4 wheel drive indicator. We thought maybe we had blown a fuse. My husband ended up stopping and taking it out of drive, then back to drive several times. Then we got the lights back on the indicator but it got stuck in 4 low so he went through the same process and finally heard the electronics kick in and now it's in 4 high. Leaving it there for now because we have so much snow. We were never successful in getting it to go into 2 wheel drive but I guess we'll worry about that when the weather warms up later this week
  • jpfjpf Posts: 496
    Could be the 4WD switch. Check out the discussions under "Chevy S10 - GMC S15 and Sonoma 4WD Issues" or "Blazer Jimmy 4WD Questions." Try a search under "switch." Good luck.
  • I have a 1995 chevy s10 2.2. I have done a lot of work to it over the past few weeks. I've finished and am getting no power though the battery is fine. I think it may be how I attached the wiring for the alternator but am not sure. I have the wire bundle plugged in. The positive to the battery is attached, but I also have what looks like a ground wire attached also. I don't know if that should be on the alternator or if I should have put it on the block.
  • gonogogonogo Posts: 879
    The battery positive goes to the starter, the battery negative goes to the engine block or any where on the engine for good contact.
  • DasyonDasyon Posts: 1
    I have a 2000 S-10. Twice today, my electrical systems seemed to restart in the middle of driving. The engine stays on, but my radio and dashboard lights all cut out and came back up twice in succession. Happened once in the morning and again in the afternoon. The both times I had just turned on my turn signal, but it does not happen all the times when I have the turn signal on. Any ideas?
  • Sounds like maybe the wiring harness at the base of the steering column may be loose. I had a simlar problem once too.
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