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Chevrolet Impala Lighting/Electrical Problems



  • No, it happens continuously. The turn indicators and etc. work fine, but the dash gauges all seem to have a heartbeat (Heartbeat of America? :{ ) Anyway, I am trying to diagnose a complicated situation with little or no knowledge. Thanks for your suggestions and any other help you can offer.
  • nelsonrnelsonr Posts: 9
    my wife works in a dealerhsip (chrysler) about the light coming on she asked one of the mechanics and he said the
    damn hated light might come on if the ignition key shows
    signs of excessive use (worn out)***this is only one of 1,000000 reasons **********************because the computer
    isn't getting a full reading of the key, and it can also
    kinda delay your ignition when starting up the car.
    he said to replace the key. I called the dealer it would
    cost me about $ 12 bucks.isn't too bad. im trying this first
  • How did this problem work out for you. We are having the same exact problem.

  • nelsonrnelsonr Posts: 9
    we have not done anything yet. the light hasn't come on since the last time I wrote about the problem. (6,days)
    but I am damn sure it will come on tomorrow just because im
    writing about it. I dont know anymore. I haven't had the chance to go get the key made, but I will some day.
    does anyone know about this problem ?????
    lowes got the key for $$4.80
    home depot for $$ 4.00
    wal-mart $$ 3.50
    dealer $$ 12.00
  • To all,
    I have recently had the same/similar problem. I now no longer have any instrument cluster light. The turn signal, cruise, idiot lights all work and so does the gear indicator (but it is extremely dim). I have checked the fuses and they all seem to be OK. I have no idea if it could be the BCM or not as it's only the illuminating lights in the dash that have been effected. Please help.
  • I have the same no start problem with my 02 impala since last May. Have been to dealer three times and they just can't duplicate it. I decide to take a look myself. Just wondering if anyone could point me to a step-by-step instructions on how to locate BCM and repair BCM connectors.

    Many thanks.
  • Hi, 0patience,

    I have the same security light/no start problem on my 02 impala.

    I tried to remove BCM from under dash but did not succeed. I can see a black box with 3 connectors ( I suspect it is BCM ). But somehow it seems hard to get it out since there is very limited space around. I tried to remove connectors first but did not find the right clip to disengage them.

    Just wondering if you could give me some glue on how to disengage the connectors and get the BCM out.

    Many thanks.
  • My IPC lights went out about a week ago. Did you get your's fixed. If so how did you repair? Thanks
  • I am having the same problem - Did you get yours fixed? Thanks
  • I have experienced no start/security problem for my 02 impala since last year. Decided to take a look by myself. Finally I managed to take the BCM off. I noticed a lot of yellow dots on solder points on the BCM board (both in front and back). Please take a look at

    Is it possible that the BCM is defective? Your inputs are greatly appreciated.
  • jntjnt Posts: 316
    I believe the yellowish material on the circuit board either is solder flux material or conformal coating. The use of conformal coating is very common on automotive products

    Solder flux is used for helping the soldering process: make solder flows better and reduce short between adjacent pins. It is no difference than the solder flux that we use at home for soldering water copper pipes.

    The conformal coating material is a liquid coating to insulate the electrical circuits from moiture condensation (that causes virtual short or detuning circuitries). That use is common in some vehicle modules

    I do not think they are electrical burn marks. Besides, if they are burn marks, you should recognize the electrical burn smell right away upon opening this box.

    I have read somewhere in the Impala discussions about the cause of most BCM module problem is on the main connectors themselves : intermitten due to loose terminals (metal mating parts of the connectors). That causes the BCM computer to go crazy.

  • Thank you very much for the information. I have decided to have a mechanic permanently bypass the passlock system. Hopefully that will work.
  • I replaced one of the modules but nothing changed. There is supposed to be a 30 amp fuse that may be the culprit but I can't seem to find it. Does any one have a clue as to where it is? There are a bunch of wires that I am afraid to move. Could it be under there?
  • Hi -

    On our '00 Impala, it has the "homelink" feature and all works fine except that the outside temperature reading is about 10-12 degrees colder than actual.

    I've noticed a variable setting, but nothing about it in manual and from "trying it" I can't seem to calibrate it.

    Does anyone know how to calibrate this thermometer setting ?

    Thanks in advance !
  • fnonefnone Posts: 4
    I have the same problem and have not yet fixed it. The calibration is for the compass zone, not the temperature on my car. I'm guessing that I'll have to replace the computer or the temp sensor. I decided to wait until I need service on something else before I have it looked at.
  • lindaflindaf Posts: 2
    I have the same problem lot of you are having. The security light will come on then off again. I have been stranded about 4 times where my car would not start after it had been sitting a while. Called dealership they advised this big routine to go through. I know I have to wait 10 mins then it will start. Very frustrating. My impala is 2001. Dealership cannot find problem unless it is happening when I bring it in. Called GM to ask for recall. Have not heard anything back yet. :sick:
  • Please tell us how you found a mechanic that could bypass the passlock system. Dealer? Independent?
  • Did the $12.00 key fix your problem? Thanks
  • My father inlaw's Impala is driving him nuts with the intermittent security light and no start condition. The dealer suggests he spend $700 on a new module but they cant guarantee that will fix it. They even gave him a copy of the bulletin, doc ID 1547837 below with his written estimate.

    "BCM - Security Lamp ON/No Crank/DTC's Set
    Bulletin No.: 04-08-47-003
    Date: August 31, 2004
    Security Light On, Engine Will Not Crank, Diagnostic Trouble Codes B2958 and/or B2960 (Repair Poor Terminal Connections at Body Control Module)
    2000-2005 Chevrolet Impala, Monte Carlo
    Some customers may comment on an engine that will not crank. Others may comment on the security light
    being on. Technicians may find DTCs (diagnostic trouble codes) B2958 and/or B2960.
    Cause: These conditions may have several different causes. In each case, however, testing of the BCMs (Body
    Control Modules) replaced for these conditions are frequently found to be operating to specifications and are
    believed to have been replaced needlessly.

    The following are the likely causes of these conditions:
    1. Damaged or loose/unseated terminals in these BCM connectors may cause a security light or no start
    ^ BCM connector C1 (24-way, pink in color), terminal B9 (white wire, circuit 1459)
    ^ BCM connector C1 (24-way, pink in color), terminal B12 (black wire, circuit 1835)
    ^ BCM connector C2 (24-way, grey in color), terminal A3 (yellow wire, circuit 1836)

    Blah blah blah, etc...etc..

    SO...they use the words "replaced needlessly" and "likely caused by" yet attached to this I have an estimate to replace part# GM10489422 module at a cost of $700 total parts including labour. I now find that the part number is an Electric Ignition Control Module. Huh??

    I want to get the BCM removed so anyone with info or tips please let me know. The yellow spots on the circuit board someone is referring to are indeed solder flux, a very normal thing to find and is NOT the problem. What one needs to look for is cracked solder connections. Those usually show up as a small crack or ring around the solder connection and most often when found are on the larger type connections such as the posts which a plug goes onto.

    Cracked, cold or otherwise poor solder connections is imho probably the single most common reason for equipment failure, of any type. The second most common problem is electrolytic capacitor failure which has become almost epidemic in the past few years. I dont see any electrolytic capacitors of crap on the picture of the BCM module.

    I'm an electronic tech and in the past 25 years or so I've repaired 1,000's of bad solder connections on circuit boards and modules in various equipment (not vehicles) and the pattern is always the same. This module is not any different in construction than one found in a TV, computer or similar electronic device. I need to get it out and inspect it closely. While it's out I will most likely resolder all connections on the plug posts and check the plugs for corrosion or other problems.

    Now I need to be able to get it out, if the father inlaw allows me to try this. Any info someone may have to get this thing out would be appreciated :)

    I would of course post my findings here if I got through with the removal, inspection (and hopefully repair).
  • Eray2000, thx for the pictures of the BCM! Those are great high res pictures and I can almost say that some of those solder connections along that row by the grey socket may be bad. Thats on the file bcm02.jpg. Fantastic shot!

    I know if that was my module, out of the car like that one is, I'd be resoldering every one of those joints.
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