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Chevy Silverado and GMC Sierra Electrical and Computer Questions



  • So did you figure out what the problem is? I have a '99 GMC truck and the instrument panel lights are all out, fuses are ok.
  • The battery on my 2006 Sierra failed. I replaced it with a new one. Now I cannot start the truck. I have a "Vehicle Security System" light on and the truck will turn over, but it appears that there is no gas getting to the engine when I try to start it. I assume I need to reset the factory security system since the battery power was removed. Can anyone tell me how to do that?

    I am in the military stationed in Germany. There are very few GM dealers over here. Any help would be much appreciated. Thanks.
  • Hi, I was wondering if you got your problem solved yet. I had a similar problem and it turned out to be a single contact bulb in a double contact socket. That will sure screw things up. Good luck.
  • Its not that simple any more. The chime comes from the drivers door speaker and is actually created by the stereo. There is one simple way to fix it replace the stereo. This will get rid of all chimes if you do not buy the harness with the chime built in. Otherwise you can pull the knee panel down and pull the cover off of the steering column and cut the key sense wire. It won't hurt anything other than get rid of the dinger. It is a light green wire coming down with the ignition wires that will show ground when the key is in the ignition.
  • I purchased a NBS 07 Sierra SLE. The driver info center displays very little info on the SLE (Chevy LS), and there are many programmable options on the SLT models (Chevy LT and LTZ). Does GM use 2 separate computers, or is there a modification (jumper removal, etc) that will allow me to enable ALL options? THANX GUYS!
  • i have a 1999 gmc 2500 pick up. sometimes it starts fine, but other times it starts but dies instantly. you can then wait with the key on from 10 to 60 minutes and it will start and run fine. i think it might be the security system shutting the fuel pump off, but am not sure. does any one know how to fix this problem or how to unhook the security system? any responses will be greatly appreciated.
  • obyoneobyone Posts: 8,054
    This might be the part you're looking for to add the Driver Information Center (DIC) to your 2007 SLE.

    SLT switch

    Several people have reported that it's a simple plug and play procedure requiring about 5 minutes to complete and gives you access but not limited to fuel mileage, range, gallons used, V8/V4 mode notification, tire pressures, tire sensor learning, key fob learning, chime volume, entry and exit lighting schemes, lock and unlock schemes (including automatic lock/unlock), unit and language choices, engine hours.

    Is this what you're looking for?
  • Yea I saw this part but I was unsure if installing it would allow me access to the additional features. If it does, then it is EXACTLY what I was looking for! THANX!
  • Ok, I have a 2000 Silverado 5.3. I started having problems with my truck a few months ago, it would be hard to start cold or hot, and i was running rich, very rich. when i pressed the gas it would stutter and then catch up with itself and i wouldnt have any problems. My gas mileage was horrible. Recently my truck cut off on me in the middle of the road, and once i got it to start again, i was like i was holding my foot on the gas all the way to the floor, but i wasnt. it would sit and idle all on its on at about 5000rpm's. put it in gear and it would calm down but wouldnt stay running long. leave it idling high on its own and it would eventually die out. the computer codes are nothing but mis-fires, several. and then it want read anything else........i need some help, anybody got an answer for me....
  • You may have to change the ECM(Engine Control Modual) modual for the engine. Put the corresponding ECM for your new engine. You can then reprogram with a Tech II or a laptop with the proper software and USB to ALDL connector. The BCM (Body Control Modual) talks to the ECM and the info does not jive with what is stored in the system hence the system lockout. Check with GM or a shop that rebuilds the ECM units to see what box goes with your engine. If your existing box is OK to use clear all faults and reprogram and I would suggest using a Tech II the low end OBDII testers cannot program and clear BCM faults.
  • fumafuma Posts: 1
    First time forum user. I keep blowing the fuse # 9--not at first---seems like it blows after it is on for a while and gets hot?--tail lights, license plate lights, dash lights and buzzer that sounds when you leave your lights on.
    Any help will be appreciated.
  • obyoneobyone Posts: 8,054
    Sounds like you have an intermittent grounding. Try checking the wires for fraying or a crack or kink. It's difficult which is why shops will charge an arm and a leg to trace electrical problems.
  • I have a 91 Chevy 3500 truck and the horn doesn't work. Does anyone have the diagram of the relay and it's location. Thanks!
  • I own a 2007 silverado and was thinking about buying the hypertech ECU programmer. I have read articles and heard that re-programming, can increase gas mileage, add horsepower, and change rev/speed limiter, etc. Has anyone tried this and what results have you encountered?
  • twagstwags Posts: 1
    Take to Lou (don't blow a fuse) Fuse :confuse: Chevrolet..north service rd a mile west of Mid Rivers ;)
  • no i didn't thanks for the help do you know where i should start I.E taillights, headlights?
  • My 2003 GMC Sierra has been great. Then my engine temperature quit reading, I replaced the sending unit, nothing, returned it and installed another one and still nothing. Now my speedometer is reading wacky, and when I cut off my engine it reads around 20-30mph. And to top it off the windshield wipers will not cut off, about a week ago it would take 30-45 seconds to finally go off after I would turn them off. Could this be the body control module? Or are all these things going out all at once? email is -Joe
  • grampy1grampy1 Posts: 140
    Check with a dealer. GM is replacing instrument panels free with issues you describe. ;)
  • I have noticed that my drivers side tail light was not working. I took it apart and noticed the middle light was black but the wires were fine. I replace the bulb and it did not fix the problem. I then replaced the circuit board. Still no fix. My brake lights and turn signal are working, so I don't believe that it is a fuse. I am baffled at this point. Can anyone please help. Also, my high beams on the same side don't work either. I haven't tried anything with this problem. Didn't know if that could possibly be linked or not.
  • I have encountered a dilemma with my 2006 Chevy Silverado Ext. Cab Z71 4X4 5.8L.
    The ABS warning light and the brake warning lights stay on. I have taken it to the dealership and they ran a scope on the electrical system. I have brakes, just no ABS. There is "no communication" with the computer on the one line yet, the transfer case can be read which is tied into that line. The grounds were checked for the module that runs under the driver's side door, cleaned and re-installed. Is there any recall out there from GM on this? My truck is just out of warranty. This has the dealership baffled as well as everyone else I've talked with.

  • I have a 2004 Silverado 1500 LT. My drivers side seat heater will initially turn off after abt 10 seconds, then wont come on all all after inital turn on. The passenger heater works fine as long as I don't try to turn on the driver side. As soon as I turn on the driver side, the passenger side clicks off. Any clue's as how to fix this besides taking it to a dealer.
  • jeh4jeh4 Posts: 1
    I am having a problem with the low beam headlights on my 1997 Chevy Silverado. The running lights come on when you turn the key or the vehicle is running. If you turn the headlights on the running lights go out and the low beams will not activate, however; the high beams work. If you place the light switch selector on the parklight selection the park lights will activate and the running lights will remain on (basically you have low beam headlights and marker lights). I changed the headlight switch but the problem persists. Does anyone have any advice?


  • azjasazjas Posts: 6
    While driving or while idling, the gauges (all of them) and indicator on my 2000 GMC Sierra SE will suddenly begin to literally go crazy! At times this will cause the transmission not to down shift when driving. I can turn off the truck/or disconnect the battery and the truck will run perfect again (Sometimes for a considerable amount of time. I checked all cables and connection - no problems found. Could this be a bad computer module? Is this an expensive fix? Where exactly is the computer module located?
  • I have a 2005 silverado. I noticed that the parking lights have stopped working. Not completely, but they won't turn on with the park light setting on the headlight switch, nor will they flash like they used to with the keyless entry. They will turn on with the headlights though. I have checked every fuse I could find on the side of the dash and under the hood. Anyone have any suggestions on what the problem may be?
  • chad8chad8 Posts: 9
    I have 01 sierra that has a very strange problem...the batteries(3 so far) I put in this thing leak(or boil) acid and don't last long...I have checked the grounds thoroughly and the cables are in good cond. I have rebuilt the alt. and also replaced it all together just to rule it out. It shows a good charge(not over) on the gauge and also with a meter. If anyone has any ideas they would be greatly appreciated
  • From what I know-experience in a GM parts department and aftermarket parts store, the ABS warning light and brake warning light at the same time may indicate a bad sensor in the ABS system. Due to the many variations within GM. Delco-Moraine, and Bendix these sensors could be located at the rotors, transmissions, or even the differential of the rear end. A computer scan may not pick this up but testing each sensor with a volt/ohm meter will indicate if it is working properly. A "good" mechanic knows how to do this.
  • 2000 Chevrolet LS P/U. A few weeks ago while driving, all of my indicators on my inst. panel lit up and all of my gauges & speedometer spiked up and down. My transmission downshifted and stuck in that gear. After I turn the engine off and then back on it runs perfect again. At night when this happens, I noticed that the gear shift position indicator goes dark. This tends to happen 2 or three times a week. Does anyone have a clue of what the likely cause is? Or where to look for the problem? Any feedback would be appreciated!

    Most likely the same problem described by "azjas" (#148 Intermittent Computer Problem)
  • azjasazjas Posts: 6
    :sick: ronnie, After waiting patiently to see if anyone on this forum would help me, I decided to look into this issue via a local GMC Dealership. I was told that the problem you (and I) are experiencing is likely being caused by a faulty ignition switch or a (ground or open) short in the wiring harness going to a sensor located in the transmission case. Although I have not had money to get my in the shop (Estimated repair cost of about $400 to replace the switch - with no guarantee that this will resolve the problem) - I plan to buy the switch and attempt to install myself - I am told that it will take some patience - but I should be able to do it.
    I just don't have that type of money at the moment, but that's another problem. I am told the switch is about $175.
  • Thanks azias!! I will take mine in armed with this information and post the results of what we do and if it gets fixed. It will be a few weeks before I can take it in.
  • Guys, I have an 03 Sierra. Though I have not had that electrical problem (YET), I have a letter from GMC that they have extended the 03 warranty for 7 years, 70K miles to correct "condition where one or more of the instrument panel gauge needles may stick, flutter or become inoperative. This may cause inaccurate readings, including the speedometer and the fuel gauge". You cannot take the truck in unless you have seen the problem. The dealer is supposed to replace the instrument panel cluster. If you have already paid for this repair, I also received claim form to GMC for reimbursement.
    FYI, during my warranty period they performed the following electrical repairs: alternator (under charge), alternator wiring harness (wild overcharge swings,bulletin PI.73170D), reprogrammed the radio module (no volume, bulletin 02-08-44-020B), replaced airbag sensors upfront, 6 software updates for the 4WD, AC pressure switch (shorted), 4WD drive light on-reprogrammed transfer case module (bulletin 02-04-21-006A).
    And now the wipers won't turn off at times.
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