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Chevy S10 - GMC S15 and Sonoma Electrical Problems



  • I have a 99 Sonoma SLS 2.2 with 62000 miles that I recently purchased. I've been noticing that occassionally, the starter motor barely turns over (at first), while other times it is fine -- doesn't seem to matter if the car is hot or cold. It appears that the battery is relatively new (it was replaced last Nov).

    Is this what starters do before they die? Should I get a new starter, or is this an electrical gremlin?


  • I have a 1994 gmc sonoma. One day I had a problem with the dash lights there were none, turn on the dome light the floor lights come on. No tail lights. Start the truck turn off dome light it stays on. I pulled it into my garage to check the electrical problems. Fuses are good. No crossed wires or fraied ones. Needless can't find the problem. So I go to mare the truck out and it will not turn over. It is not spraying. Fuel pump does run. Can anyone help?
  • ok. so my truck is an 2003 S-10 with 65k on it. about two weeks ago, it started making this really high pitched buzz from the center console behind the dash and then the RPMs dropped WAY down when it idles. to the point it stalled when i took my foot off the gas (it's an automatic, and therefore not supposed to stall.). i had a mechanic friend look at it, it has a battery, the alternator is good, but we couldn't get it to start. i had it towed and my shop couldn't replicate the problem, i took it home. i just took it out tonight and it started fine but all the warning lights on the dashboard lit up for a second, then went out. then went on. then went out. it said my parking brake was on, it wasn't, and it said my seat belt wasn't on, it was. it didn't stall, it idled fine, and then the whole thing shut off, and the clock on the radio reset itself. the dome lights still work, the radio works, but it wouldn't start at all. i waited about two minutes and it started fine and i was able to make it home.

    can anyone tell me what the heck is going on? they plugged it in and couldn't get any codes, and all the fuses are apparently ok.

    i'm a fairly small woman and i have to drive through some fairly rough neighborhoods on my way to campus, and i really don't want to get stranded, especially since i have no idea what the problem is. HELP!!
  • no i was still trying but i gave up and bought another truck and am using that one for parts but i dont think it was the display itself i tested all the plugs for power and had none. and couldnt find out why.
  • I was installing a cd player in my 97 s10 and when i pulled the dash apart i broke the hazard light switch off. Now when i put the brakes on both the signal lights come on, so i got a buddy that works at a junkyard to find me one , but the only one he could find with no cruise control was out of a 98 s10 . Will this one work in my 97 s10?
  • There should be a switch on the brake pedal somewhere locate it and replace it it's probably bad or needs adjustment..
    ANY IDEAS!!!!!
  • Replying to: awade (Jul 18, 2007 7:49 pm)

    99 out of 100, it's always a bad ground when things look alien.
    Ground will seek out anything to make a circuit, as in making false lights light up, dimming of others and so forth.

    Check ground connection at radiator core support from battery terminal.
    Also add a ground from battery to other body panels, fender, back to the engine anywhere. Use #10 gauge wire.

    Replace poor looking battery cables.

    Sand clean the body ground connection and use a good grease before mounting it.

    Clean and wire brush cables and battery terminals so the shine, apply grease on connections and clamp tight as possible so that if you grab cable it cannot move or twist at the battery connection.

    Good Luck
  • Hey i have the exact same truck with the exact same problem any idea of what it is have you got it fixed yet? i was thinking it was the head light switch but i dont know just a guess. Please respond asap.

    Thanks :sick:
  • Is This article for the 96 Headlight problem. My headlights go on and off when i drive. where do i look for the ground wire. can you be really specific on how i can find it.

    Dan :confuse:
  • First.

    Take the Battery Out.

    While your messing around, put battery on charger, so it's at max output when your ready.

    Use jumper cables from battery back to vehicle to make tests as you progress as battery is charging.

    With the Battery OUT of vehicle.You can see where the cables go.
    Make necessary repairs to battery tray if in rough shape.

    You also may have inherited someone else's nonsense.
    I've seen some pretty Ugly results of what some people do,

    Look at the ends of cable very closely.
    REPLACE them if they look shabby at all.
    In other words, IF they don't look like new at both ends. Ditch them.

    IF the cables are long enough, CUT off the Garbage, and remake new ends on them. SOLDER the new ends on if possible.

    If you see corrosion going deep down into cable ends for several inches, then toss them.

    Brand New Vehicles Came with dual lead ground cables for 20 years.
    LOOK at where this smaller CABLE branching off from Battery ground is attached to. This is usually the Radiator CORE SUPPORT. If it's been replaced correctly.

    IF NOT_ THen ADD a ground wire of #10 Gauge Wire [MINIMUM] to the GROUND at Battery to the CORE SUPPORT.

    The alternate to using #10 wire is it's about 1/8" thick copper core.
    Use wire with larger copper diameter, not smaller.

    In a desperate pinch, one could use the stiff house wire for a temporary fix, but it's too stiff, and road shock will break it.

    Fasten an EYE on both ends of #10 new wire, and use the correct size for the battery bolt.

    Using a #10 self tapping hex head sheet metal screw mounted in cordless drill with hex head driver that fits screw, drive it into the back side of CORE SUPPORT.. This is the frame work holding the headlights and radiator.

    Use a washer under bolt to the connector. Apply grease to connector before attaching to CORE support

    The reason I mentioned in last post to make more than one ground wire of #10 wire attached to battery IS,

    to provide a solid ground from one panel to the next.

    Other points as well to include are the Engine Block, Firewall, etc.

    MOTOR mounts can be a huge issue of blocking a good ground back to the body and frame.

    You can also continue a second ground from CORE Support back to the engine. This un-clutters battery connector.

    Usually the best spot on the engine is the alternator bracket, or something similar.

    Make sure the movement of engine does not wear on the wire, or too short.
    Now near the back of the engine, make one going to the fire wall.

    NOW, your fully grounded up front.

    If the vehicle is rusty in general, then you may have to run a separate ground all the way back to the tail lights for example.

    One wire looping from light to light, like you would do if it was a Utility Trailer.

    Examine the headlights ground wire to make sure it has a good path.
    This wire from plug on back of bulbs could also need to be remade.
    I usually just purchase new head light plug pig tails. Cheap Part.

    This step can also help boost the alternators output as well.

    Use wire ties to keep things neat and prevent unnecessary damage from sharp edges.

    Murphy's Law will be right at your heels, so you will have to out smart him at every step.

    Might be over kill and winded for some, but some will only have to do it once.
    Later, Good Luck
  • Post disappeared, what ever.

    But if dimmer is bad, and very common, they are sorta expensive and totally a pain to install.

    Auto Zone rents out the tools free to use.

    You'll need the steering wheel Puller for one and the Snap Ring compressor tool as well, or you will swear words that are heard for 5 miles.

    GM never could make this switch from day one correct.
    I have the same one in my Caddy as well. And this was a severe pain with tilt, telescopic column.

    I was forced to remove the entire column out of the car.

    I have a 35 year old Volvo 164 where the dimmer on the column still works perfect. People talk with this lever vs the horn.
  • so you think it could also be my dimmer switch. why would it be that and not my light switch. my dimmer runs fine i think it doesnt give me problems but is that why my lights would go off sometimes..... im very confused please help. :sick:

  • I have a 95 sonoma 4x4 reg. cab ,my headlights are so dim its like my parking lights are brighter. I put h4 high reflective bulbs in, no help. I tried taking out the day time running light modual, no help.I have checked all the grounds and even added a few ,still no better. I am hoping some one can help, it would certainly be appreciated. thanks mags468
  • gonogogonogo Posts: 879
    What voltage are you getting to the bulbs, sounds like a resistance in the circuit.
  • thanks for your reply. i'm getting 12.4to12.7. i also ran pos. & neg.10g direct from the batter to see if that made a differance, none. witch would tell me it would be the lights, but they are silverstars witch are one of the brightest. its got me stumoed.
  • My Blazer, at least once each winter has an electrical problem with the brake lights. The brake lights for some unknown reason will not shut off, even without pressure on the brake pad or when the vehicle is shut off. If you are not paying attention, it will lead to a dead battery. Is this an isolated case with my vehicle or is it systemic with S10s that year? What is the corrective action if any?
  • Sounds like your getting moisture in your brake light switch. locate your switch and spray it with some w-d 40, that should help keep the moisture out. I hope this helps, mags.
  • My Blazer, at least once each winter has an electrical problem with the brake lights. The brake lights for some unknown reason will not shut off, even without pressure on the brake pad or when the vehicle is shut off. If you are not paying attention, it will lead to a dead battery. Is this an isolated case with my vehicle or is it systemic with S10s that year? What is the corrective action if any?
  • I have a 1998 GMC Sonoma 2.2 ltr. 4 cyl. auto that I need to replace the throttle position sensor on. I wanted to know if it is hard to do, and how to do it?
  • Well this is to let everyone know these supposedly HI! OUTPUT!! lights are only 5% whiter, not brighter. What a wast of $100.00. So don`t get scammed like I did. Thanks for this sight Mags.
  • sjj62sjj62 Posts: 2
    Where is the turn signal flasher located on a 1997 GMC Jimmy 4WD? I bought a replacement turn signal flasher ( a round plastic module with 2 prongs) but have no idea where or how to replace it. I checked under the dash on the driver side but have no clue where it goes. I see a black plastic module with all of the wires going into it but don't see how to access it or how it comes apart or if the flasher even goes in there. I checked in the glove box and under the dash on the passenger side as well.
  • sjj62 the turn flasher is behind the knee panel just about above trans. you will have to remove the panel to find it. good luck mags.
  • Check under the hood, most GMC's and Chevy's have a large fuse box under the hood that contain the large fuses.
  • I have a 1991, S10. I turned on my radio, it went dead like it didn't have enough power. I push my horn and it sounds like a relay behind the dash is buzzing, the horn does not honk. My dome light wont come on when the door is open but it will slightly light up when I push the horn or cigarette lighter in. Is it possessed? Or is there a simple solution to the problem?
  • I have a 95 Chvey Blazer that keeps blowing the 20 amp fuse for the dash board panel. Half the gauges go along with the speedometer and if running at night with the "lights on" indicator buzzes continuously. However other important operating functions that also proper transmission shifting, and direct charging of the system by the alternator. If this fuse blows the car runs only on direct battery power. This issue seems to happen only during cold or wet weather or when the engine is cold. However if I idle run the car warming it up, for a while hopefully, without draining the battery I can put a new fuse in and it won't blow and the car runs fine. Brought it to a Chevy dealer and they too are at a loss. Thanks
  • sjj62sjj62 Posts: 2
    Are you talking about the lower trim panel just above the trans in the middle if the dash just below the AC controls?
    Or the panel on the driver side under the steering wheel?
    The 97 Jimmy has the automatic trans shifter on the floor between the 2 seats. Just in front of that on the dash is the cigarette lighter and utility outlets with the AC above that and the radio above that. When you remove the center lower dash panel you get the plastic vents from the heater right behind it and the lighter.
    I must be blind because I just can't seem to find the turn signal flasher for the life of me.
  • The turn signal flasher should be just to the left of the cig. lighter . There will be 2 canisters side by side. Thats where my 95 is & Chilton does not make any refferance to any differance with floor shift or air. So to my best knowleged that is where it is. mags
  • Obviously there is an amp spike or short intermintant. The easiest to check first and most likely the cause is the alternator. Even though it is charging, there may be an intermitant short at the internal regulator. On your alternator there is a plug with some small wires leading to it. Next time you think that the fuse should blow, disconect that plug to your alternator prior to starting the vehicle. This will turn your check engine light on and prevent charging, but its just a test. If the fuse doesn't blow, I would be very suspicious of an intermitant short in the regulator. Ok, try this a couple of times. Don't reconect that plug until the engine is off. By the way, is this fuse #4 20amp ? If this doesn't work, post more info such as engine size, production date, fuse # location, auto or manual trans, and I'll give you some other ideas you can try. Good luck.
  • Hi Mickeymouse2:

    I just wanted to add one bit of info. The fuse will blow when I turn the key to the first notch that sets the panel lights on (i.e. check engine light,air bag seat belt light etc). Also the problem is intermittent and doesn't happen all the time cold and wet weather seem to aggrevate the problem otherwise everthing works fine.. The Chevy dealer is at a loss! Can this still be an alternator problem?? Yes it is fuse #4 Gauges. Auto Trans 1995, 4.3 liter voretec V6. Thanks
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