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Chevy S10 - GMC S15 and Sonoma Electrical Problems

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  • alisha0218alisha0218 Member Posts: 1
    I have a 99 chevy s10 and the last few days I have been having problems with my dashlights, gauges and power locks. I was driving and my gauges flickered and my cd player quit and my clock reset. Tonight when I started it, my parking light came on for a bit and when I got out, my interior light wouldn't come on and my power locks quit. Help! I'm a girl and I don't know much bout electrical stuff.
  • mags468mags468 Member Posts: 10
    Hi Alisha0218. the first thing i would check is the fuse, the fuse block is on the left end of the dash. If the fuse is ok, make sure you don`t have a tail light bulb burned out, i know that probably sounds strange but they are tied together,if not then it sounds like you have a short in your dash light moduel, which is located under the knee panel, wrapt up in foam & tape it is not right out in the open & does`t look like a moduel it is actualy a printed circuit. i wish you luck, mags
  • jhchallisjhchallis Member Posts: 4
    I have a 1995 Sonoma, 2.2l 4cyl, Manual trans, 2WD that I am having trouble starting. Initially I had a problem when driving that I would lose all power and the engine would die. I would nurse it to the side of the road and let it sit for a few seconds and it would start back up, as long as my dash lights came on (if they didn't, it would not start). I found that the battery cable to the starter was loose and tightened it. I had no problems for about a month or so.

    Last night, it did the same thing. It started back up and ran fine, but when I got it to my house it will no longer start. Today I checked the starter wires and they were tight. I removed the starter and had it and the battery tested, both were fine. I replaced the starter cable to the battery. I conducted continuity tests on all wires leading from the starter, alternator and into the dash and all seems fine.

    The current symptoms: it will turn over fine, but will not start. The dash lights come on very dim (barely able to see) except for the seatbelt warning light, which comes on bright. All accessories work fine. It has OBD-II, but I cannot find a scanner that will read it (I guess the dealer will have to do it at some point). Any ideas?
  • gonogogonogo Member Posts: 879
    Check out the ignition switch, it is a known problem.
  • jhchallisjhchallis Member Posts: 4
    This may sound a little dumb, but how do I check out the ignition switch? I am mechanically inclined and know how to test for connectivity, but that just about reaches my electrical abilities. Thanks.
  • gonogogonogo Member Posts: 879
    Well it is best to have a wiring schematic, you need to know if proper volts and amps are coming out. A test light is best.
    If you are at a dead end you could just change it but I like to be sure, hate replacing good parts.
  • sprjrivsprjriv Member Posts: 2
    Hello,

    I see there are a lot of similar problems out there, but I was hoping someone had the same as mine.

    :sick: I have a 94 GMC Sonoma 2WD with the 4.3L V6. The other night all of a sudden the rear parking/running lights just stopped working. :sick:

    The things that aren't working are the license plate lights and the running/tail lights. The bulbs themselves work fine when I hit the breaks, and for the blinkers. The front running lights also work fine, as do the head lights.

    The fog lights aren't working but I think it is because the bulbs are burnt out, but the toggle switch works and lights up.

    I have checked the fuses inside the truck, and the bulbs. They all seem to work. The front running lights are a little gimmicky, some times I have to turn on the head lights or the fog lights to turn on the parking/running lights, but the front ones work fine.

    Does anyone have any ideas or has solved the same or similar problem??

    Someone told me for those models there was a seperate fuse/ fuse box for trailer wiring, and that if it popped out that it would pretty much cover what is going on.

    Any ideas please help!! Thank you!
  • jhchallisjhchallis Member Posts: 4
    You were correct, it was the ignition switch. When this issue first started that was my first thought. But, I had two different mechanics tell me that the ignition switch would be the last thing to go. I replaced it today and it seems to be working fine. Thanks for your help.
  • rdracing14rdracing14 Member Posts: 3
    I am having trouble with my 97 GMC sonoma 4.3L V6. It is not getting any fire to the coil. I have replaced the coil, distributor, cap, button, pickup, plugs and wires, crank sensor, coolant temp sensor, and swapped out computer. Still no fire but it will turn over. Battery is good. Friend of mine hooked it up to a computer and its not reading any codes! What the heck can the problem be. I would really appreciate any advice because I am out of ideas! Oh and by the way when the truck broke down it backfired and blew out the top of a flowmaster!!!

    Thanks in advance for any advise!
  • gonogogonogo Member Posts: 879
    Thanks for the update.
  • hedrra3hedrra3 Member Posts: 1
    I have encountered an issue with the tail lights on my 1999 S10 4.3L V6. Here are the symptoms:

    When ignition is off:
    - Brake lights on both sides work fine

    When ignition is on:
    - Left brake light is out, right brake light works fine
    - Left rear turn signal is out, right rear turn signal works fine

    Ocasionally, it decides to work correctly and there is no issue, but 99% of the time this is happenening. I have already replaced the left rear bulb, the flasher, the brake relay, and I have unplugged the cables near the back and checked for corrosion on the connectors for the tail light wires. None of these have helped. Can somebody give me an idea of what's going on?

    Thanks!
  • rdracing14rdracing14 Member Posts: 3
    So after changing all of the parts and nothing working I went to the GMC shop and talked to a friend of mine. Come to find out most sonomas have or will have this problem at some time or another. I thought I would pass on what he told me. There is a wire leading to ignition module that breaks. Its something easy to over look so if anyone else has any of the same problems that I had you may want to check it out. My truck is up and running like new! Cant believe I went threw all that trouble just for it to be a broke wire!
  • gonogogonogo Member Posts: 879
    Thanks for the heads up, throwing parts at it can cost.
  • 58flh58flh Member Posts: 1
    :sick: i am goen through the same sh....t help,,let me know what you found out....exhaust aint cheap hugh??? scooterroo
  • mikeysonmikeyson Member Posts: 4
    1999 s-10, 2.2 manual tranny.

    I am at a total loss on this problem, here's the issues:

    *When trying to start, it starts in a pattern every time:
    engine turns 3 or 4 times, pause (repeat 3 times), then engine turns until start.
    *headlights
    not working, doesn't matter if ignition is on or off. daytime running lights do not work either. Dash light for brights is always on, dimmer switch does nothing.
    parking lights come on
    *taillights
    headlight switch on or off brake lights are on
    headlight switch on -> side running lights come on
    press brake pedal while engine is running, engine dies
    remove brake light fuse, can press the brake pedal and engine does not die
    cab brake light functions normally
    *ac/heater fan
    switch on, engine dies
    the car will not start, (but engine turns), when switch is in any on position
    *hazard lights
    ignition on -> hazzard lights on solid
    ignition off -> hazzard lights function normally

    lots of odd issues eh? There are no engine error codes and everything else appears to function normally. Alternator was replaced, 6-8 months ago and start a month ago. Nothing recently aside from those. Any ideas before I start thowing money away at a shop??? Help!! :)
  • gonogogonogo Member Posts: 879
    Check all the grounds you can find, weird symptoms are usually grounds.
  • gcebulkagcebulka Member Posts: 1
    Hello All,
    I have a 2001 S10 FWD. I cannot get my high beams to stay on, nor will my fog lights work. If I pull and hold the the dimmer lever, the high beams will come on, but, once I release the lever, they go off. The fog lights will not come on at all, even after flicking the level a couple of times.
    Anyone out have an idea as to what the problem may be?
    Thanks,
    George
  • truc77truc77 Member Posts: 5
    I have a 98 S10 ,,,,,,I only have 5.1 volts at my fuel pump, when I hook 12 volts up to it pumps fine but the truck still wont start. If I pour gas directly into the throttlebody it will start and run til the gas is gone.. replaced relay, but still 5.1 volts any help would be greatly appreciated, Curt
  • gonogogonogo Member Posts: 879
    Check for 12 volts at fuse Cluster 11, if low volt replace ignition switch.
    The power feed to the pump also powers the injectors, hence no start.
  • truc77truc77 Member Posts: 5
    the ground checks out at 0 ohms to the connector at the rear. I have 12 volts entering and leaving the fuse cluster, something in between there has to turn it off when the pump make 55lbs, or does it shut off itself??
    If I pour gas into the throttlebody (or what ever it has) It starts, so I assume the injectors are good.
  • mickeymouse2mickeymouse2 Member Posts: 161
    Sorry to jump in here late. Your fuel pump is only going to come on for about 2 seconds. Its called a 2 second prime by the PCM. Your tested fuel pressure at 55psi is with in specs. If the vehicle will start breifly by putting something flamible in the throttle body, verify injection pulse and power to the injectors. The pulse is controled by the PCM making use of a cam sensor signal, they are powered by the PCM. If you have power to the fuel injectors but no pulse while cranking the engine, most likely cause is a failure with the cam sensor. You can test for power at the injection plug with a test light, ignition key on run position. You can use a test light to check for the pulse also, but just buy a noid light and plug it in the injector plug and crank the engine. It will blink while cranking if the PCM is pulsing the injection system. Repost after those test.
  • gonogogonogo Member Posts: 879
    A bad cam sensor will not cause a no start, the PCM will just revert to the default
    setting and put the check engine light on.
  • gonogogonogo Member Posts: 879
    Lets start from the beginning, will the pump run 2 seconds with the key on run. Not jumped, but wired factory.
    When you put fuel in the intake you are not using the injectors, you by passed them.
  • mikeysonmikeyson Member Posts: 4
    All the grounds look good. Also tested the brake light switch and fan switch. The brake lights will go out if I remove the fuse, and I can hit the brake pedal okay at that point.

    Does the lighting link in through the computer? Not to focus so much on the lighting since turning the fan motor on also kills the engine. Does that link into the computer as well?
  • stumannstumann Member Posts: 7
    I've replace the starter twice on my 99 S-10 2.2 5-speed, 132,000 miles. This time I replaced the starter and flywheel. F'wheel had a broken tooth. It still acts strange. The engine tries to "kick back" when cranking. Reminds me of a wet distributor cap from years ago. I removed the ECM fuse and it cranks fine, so I'm pretty sure it's ignition related. Once it starts, it runs perfect, no check engine light, no codes. Someone suggested replacing the crank sensor and the cam sensor. I did, no change. I'm know I'm going to ruin another starter and flywheel if I don't solve the problem. Has anyone heard of this problem before? I do have new plugs and wires on it, but I've never replace any coils.
  • gonogogonogo Member Posts: 879
    I reread your first post, you have quite a mess there. Little history, did this just happen all of a sudden or was there work done or was it jumped.
    You say no head lights, I would start there first, with every thing off the head lights will come with the switch. Unplug one of the head lights, with switch on should be power there, I like to use a 12 volt test light in a situation like this.
  • stumannstumann Member Posts: 7
    Well, I took a chance a bought a couple of coil packs and installed them. That fixed the problem!! I hope this post may help someone in the future with the same troubles.
  • mikeysonmikeyson Member Posts: 4
    I will check the power to the headlights today. however I'm thinking there will be no power since the headlights do not come on (with the headlight switch on, the parking lights come on).

    So, here's what happened that day...I drove the car to work and everything was fine. I went back out after work and the car seemed to start normal, however I noticed the headlights were not on and the brights icon was on in the dash. I didn't really think anything of it until I hit the brakes and the engine died.

    The only work that has been done recently (aside from oil changes) is a starter replaced about a month ago and the alternator around 6 months ago. I did jump my sisters car a few weeks ago (not sure exact date).
  • gonogogonogo Member Posts: 879
    Have you had it checked for codes? You could still have power to the head lights and they will not come on without a ground.
    I own a 99 Sonoma 2.2 auto. I have lots of information on the 99, the head light schematic looks like a bowl of spaghetti.
    The 99 also has a BCM, Body Control Module, not sure if that could cause your problem.
  • mikeysonmikeyson Member Posts: 4
    No engine codes. I have the Chilton repair manual which has several wiring diagrams that I've been looking over. It almost looks like there's 2 seperate issues, the lighting and the heater. I'll check back once I look at the power to the lights...
  • chevy_durangochevy_durango Member Posts: 1
    Hi there,

    this is the first time posting on this forums and only because i'm about to loose my job because my truck is making troubles.

    I bought a 83 s-10 (2.8l v6)from a car shop last week. when i testdrove it everything except the headlights worked fine. they said they're gonna fix it and i can pick it up at night. when i came to pick it up i had to compression start the car but the headlights worked. i drove for 5 minutes and the lights started getting dimmer and the turnsignals stopped working.I pulled into a gas station, turned off the car, turned it back on and it worked fine again. 15 miles later the voltage dropped all the way down and the engine died. My buddy came with another batterie and i could drive it to my house. The next day i drove it all day (never used the headlights) but at night and probably 20 minutes after i turned on the headlights the voltage started dropping again and i turned the car off before it could die again. Then nothing worked anymore, not even a click to start it.
    Next morning it started without any problem and again ran all day. even had it running with the headlights on for a while and it worked fine. then again at night i had the same problem and i turned the car off(had to jumpstart it the next day).
    Autozone tested alternator and it was fine...
    the wiring seems kinda screwed up so i wonder if i could have a short

    any helpfull tip is much appreciated !

    thx in advance
  • sn4ck0sn4ck0 Member Posts: 8
    Hello all,

    I've a 95 S-10 2.2l, and I'm trying to work on fixing my heater/a/c issue, and I believe that it is a grounding issue, but I'm unaware of where the grounds are for this.

    So if any of you have or know where I could get them, I would be much, and greatly appreciated.
  • dehdeh Member Posts: 1
    I have a 1985 GMC S15. When the lever is right, or left all of my turn signals come on at the same time. Would there be any help out there for what the problem may be?
    Thanks...
  • farside4farside4 Member Posts: 3
    I recently towed a friends trailer and noticed when unhitching that the running lights were out. And also noticed that the driver side parking lights were out as well including the license plate light. I have a brake light and turn signal just no parking light on that side. The passenger side is working fine and all other parking lights are working correctly. Is there by chance a inline fuse that i missed cause i have check all the fuses that i know of in the fuse box. Any suggestions.
  • farside4farside4 Member Posts: 3
  • farside4farside4 Member Posts: 3
    found problem looking now a replacement fuse box..
  • bgolenorbgolenor Member Posts: 2
    just had samething fixed
    replaced multi function switch in steering wheel worked 5min he said switch burned relay out. replaced it and working fine.
    i would try relay first
  • bgolenorbgolenor Member Posts: 2
    i had same problem with my 2001 s-10
    garage put in muti function switch in steeringwheel work for about 5 min.
    than a relay because old switch burned old relay.but works great now.
    so i would try relay first


    GOOD LUCK
  • polanderpolander Member Posts: 3
    The daughters 1991 GMC Sonoma with a 2.8L V-6 died on the side of the road and was towed home. A friend of hers put in a spare battery he had, checked the fuel pump relay, said it was bad, wiggled it and the truck started. She bought a new battery, put a few miles on the vehicle that night, next day a few more miles then another tow home. She bought a new relay which I replaced with no success. I heard no fuel pump noise and lowered the tank. Another "helper" showed up, I handed him a tester and he said I had voltage to the pump. So I replaced it. Hit the key and it wouldn't start. I listened for the fuel pump and heard no noise. I tested the old pumpto find it worked fine. Checked power to the tank with a Multi-meter to find 5 volts and that my helper didn't realize a dim bulb meant low voltage. I checked the wires from tank to hood, no breaks or fuse links. Pulled apart the multi-pin connector on the firewall to find it full of axle grease instead of dielectric grease. Cleaned with contact cleaner, re-assembled, hit the key,heard the fuel pump, nothing. Pulled the fuel filter, got a shower of gas, replaced filter (the old one clogged so badly it wouldn't pass air). Hit the switch, nothing. Checked voltage at tank and it was back to 5 volts. Removed and re-cleaned connector, still nothing. Put the charger on the new battery. Tested Ignition Module at the parts store. It was defective so I replaced it and still nothing. I've cleaned grounds and checked terminations (after I ran a wire from the battery to the disconnect on the fuel pump0. Still nothing. I probably fried the new fuel pump with all of the twisting and tugging. I know that was a lot to digest. Tomorrow evening I'll drop the tank again and try again. HELP ME PLEASE, My hair is gone! Thanks
  • greasymonkey3greasymonkey3 Member Posts: 7
    hello, iv got a 91 s-10 2wd with a tbi 4.3 auto tranny. well my truck quit running and started blowing ecm fuses. so i pushed it down the road and decided to put a new fuse in it. well it started working again and i drove the truck for a couple of months like this. well a couple of days ago my truck just quit running. and smoke started coming out form under the dash. it melted the fuse it didn't just blow it it litteraly melted it! so i towed the truck home. started inspecting things and testing stuff. well i went over any visible wires and checked the pump its still good. but i found a couple of bare wires inside the throttle body they go to the injectors. so i replaced the wires and injector plugs. put a new fuse in it and it doesn't blow the fuse but it wont start either doesn't even fire. so i put power directly to the pump to make it run it still didn't do any good and i know its pumping i took the line off and tested it i put fuel in the throttle body and it started. i have a parts truck like it so if you have any ideas id appreciate it. thanks
  • mickeymouse2mickeymouse2 Member Posts: 161
    If the truck will run with some other type of flammable spray, sprayed into the throttle body, its most likely fuel related only. Because you tested the grey power wire to the pump and it only had 5v. Suspect sorted assembly for fuel pump or power delivery issue. Unplug the harness and check voltage again. If you now have 12v, you have a short in either the pump or the assembly hanger. Remember if 12v is being supplied and there is a short somewhere, your meter will read less than 12v, depending on the amount of amps the short is. GM fuel pumps short quite often in the assembly hanger where the wires go through to the pump. By unplugging the harness and checking the voltage this way, you will know only then if the proper voltage is trying to be supplied.
  • mickeymouse2mickeymouse2 Member Posts: 161
    If the truck will run with some other type of flammable spray, sprayed into the throttle body, its most likely fuel related only. Because you tested the grey power wire to the pump and it only had 5v. Suspect sorted assembly for fuel pump or power delivery issue. Unplug the harness and check voltage again. If you now have 12v, you have a short in either the pump or the assembly hanger. Remember if 12v is being supplied and there is a short somewhere, your meter will read less than 12v, depending on the amount of amps the short is. GM fuel pumps short quite often in the assembly hanger where the wires go through to the pump. By unplugging the harness and checking the voltage this way, you will know only then if the proper voltage is trying to be supplied.
  • greasymonkey3greasymonkey3 Member Posts: 7
    im trying to remove the fuse box on my 91 s-10 i dont know how to get to what ever is holding it on can some one help me? thanks
  • polanderpolander Member Posts: 3
    Thanks, I replaced the wires from the tank to the terminal block under the hood and the pump worked. Still wouldn't start. I have fuel in and out of the throttle body, power to the injectors when I turn the ignition to the on position. Since the fuel filter was so filthy I decided to remove and clean the injector module. Inspection revealed much dirt and a bit of rust on the pressure regulator diaphram so I cleaned the unit, rebuilt the regulator, reassembled and reinstalled the unit. Still nothing. Any thoughts?
  • mickeymouse2mickeymouse2 Member Posts: 161
    Now that you have fuel comming out of the injectors, sounds like the fuel issue is resolved. Spark plugs may have gotten fouled with all the cranking. Check for spark also, on more than just one wire.
  • polanderpolander Member Posts: 3
    Well, at that point, I didn't have fuel coming out of the injectors. I was cautioned about using DIY cleaning chemicals. (see my screen name) I filled the unit with cleaner and let it soak for a while. I then rigged up a "gizmo" of clear tubing that let me have cleaner to back wash the injectors by applying low air pressure. That did the trick. The dirt (or ?) had hardened in the injectors like concrete. (maybe one of the kid's friends was pissed) Put it back together and drove to the new O'Reilly's in town for some high end fuel injector cleaner. Lucas fuel injector cleaner was on sale 2 for $6. (limit 12 per customer) I stocked up. Thanks to all for the help. Sadly, spending so much time under the hood and under the truck revealed emergency brake cables that need to be replaced, wheel cylinders that are leaking, valve cover gaskets that are failing, and a radiator that probably needs to be flushed. Again, thanks to all.
  • sinfulonesinfulone Member Posts: 1
    What did you do to fix the problem? I have a 95 that is doing the exact same thing.
  • timmah1987timmah1987 Member Posts: 2
    OK so I did a bonehead move today... took apart the wiper motor connector to clean all the contacts, and didn't keep track of which color wire went in which socket!!! There are five wires, two at the top, a black wire in the middle, and two at the bottom.

    I'll label the sockets like this, looking INTO the connector at the metal connections:
    --------
    | 1 2 |
    | - 3- |---
    | 4 5 |
    --------

    where the line by the "3" is where the tab on the connector is. I'm fairly sure that 3 is the black wire, but if someone could be so kind as to peek under their hood and tell me where all the other wires go? Don't worry, I won't be making this mistake ever again!!!!

    Thanks tons,
    Tim
    (gotta love ASCII art....)
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