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  1. #1
    Jr. Apprentice reaper's Avatar
    Join Date
    Nov 2009
    Western Nebraska (almost Colorado)

    Default Newbie with a researched question...Resolved!!!

    Hello all my name is Dwayne and I am from western Nebraska. I just got a killer deal on a 1999 k2500 burb 4x4. 9" of prof installed lift, 35" tires, the works. It had some electrical problems when I got it and that is the reason I got it for the price I did. I am not new to mechanics, as I work on Semi trucks all day long. However, this thing is driving me mad. Once again I have a 1999 k2500 LS 7.4l Fully loaded with leather, power and heated everything. my problem is that the dome lights stay on all the time if I don't remove the fuse. (#3) I have tested the light switch, all door switches, light housings and all the wiring. also the radio shuts off with the key, and the PO told me that radio used to stay on till a door was opened. I read about the LCM (light control) under the dash. I have looked for this thing for hours, and cannot find it. I purchased an alldayadiy subscription and seen that the luxury model of this truck may have a BCM (body control). Is this located on the left of the steering column under the dash? What all does this thing control? Also what else could this problem be caused from. Other than this and the small leak from the transfer case to trans split gasket, this burb is great. 70k miles, no wear and tons of upgrades. I will make an intro thread for all of that. just need to find this problem for now. thanks all for the future help, and I hope to help some in the future.
    Last edited by reaper; 11-19-2009 at 12:30 PM. Reason: update status

  2. #2


    Is the instrument cluster dimmer switch turned ALL the way up by chance? That would cause the dome lights to stay on........

    That's one thing you didn't say you checked.......

    Airforce Veteran (7 years)

    NRA Life Member

  3. #3


    Other than that, was there an aftermarket alarm installed in the truck? Perhaps there's a stray power line that's keeping them powered up. Either that, or is any other powered accesories like aux lights or something were installed, that might be causing it. I hate electrical issues because of this precise reason. Good luck hunting!

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half

    There are 10 kinds of people, those who understand binary, and those who dont...

    Remember kids, the only difference between screwing around and science is writing it down- Adam Savage

  4. #4

    Join Date
    Jun 2006
    River Ridge Louisiana-4 miles W of New Orleans-didn't flood-water stopped 800 yards away.



    You'll love that Suburban.I bought mine-1998 2wd 1500 5.7- 2.5 years ago with 195,000 miles on it.It has 211,100 miles now and still runs great.We use it for driving trips,and in case we need to evacuate from New Orleans suburb with 2 dogs, 4 cats 3 adults. Cheap, huge , versatile and reliable can't beat that.

    This is something you must have already looked into, but just in case.
    My Suburban has a dome light and it stays on for about 15-20 seconds after I shut the door and walk away. I can see how that is useful, but it kinda puts me off wondering if it is actually going to turn off.
    My point, is there must be some sort of time delay switch that allows this delay-something that is somehow tied to opening or shutting the doors,I think. If this switch/timer is screwed up, the light won't go off.

    It is almost certainly that freakin "light control switch" under the dash, or a fancier BCM switch you are looking for.

    Like others said- did the PO do any electrical work-fancy radio, alarm etc? PO are notorious for screwing up this sort of installation.

    Are all the radios( my old persons way of saying the electrical entertainment "stuff")the original OEM items? If not maybe he screwed up?

    Is the bulb the correct bulb?I don't know how or why an incorrect bulb could cause such a problem, but worth checking.Doubt it could cause a staying on problem instead of a won't go on problem.

    Sorry I couldn't be more help-this is stuff you have already checked no doubt.

    Enjoy the Suburban-you'll fix the light-one of those piss off problems you eventually solve by gritty determination or pure luck.
    1998 suburban-
    1/2 ton

    199500 miles

  5. #5
    Jr. Apprentice reaper's Avatar
    Join Date
    Nov 2009
    Western Nebraska (almost Colorado)


    I forgot to add that I previously disconnected all of the door switches one at a time, and also had the headlamp switch itself disconnected at the same time. All of the electronics in the truck are from the factory, and I don't see anything messed with on the wiring to them. I checked all of the door switches again for continuity to ground and found none. I crawled up under the dash today and looked for the light control module but still cant see anything that resembles what it looks like or the color combo I see on alldata. There is a silver computer looking box about 3"x3" under the dash on the left side of the steering wheel. when I turn the key switch on this box clicks a few times. Is this the body control module? it has 2 plugs I believe, one with a lot of wires and one with 5. if not is there a different location for the light control module? Thanks everyone for the help so far.
    That which does not kill you...will only make you stronger!!!

  6. #6
    Jr. Apprentice reaper's Avatar
    Join Date
    Nov 2009
    Western Nebraska (almost Colorado)


    I got this problem repaired yesterday. Here is what I found. While working on the lighting problem, I found that every time the door was opened, and I pressed the override switch, a relay clicked under the dash. After about 30 minutes of searching I found a black box tucked between the steering column (right side) and a bracket (above the brake pedal). while trying to figure out how to remove it, I somehow damaged it. I figured this out while trying to lock my doors and the drivers door, or remotes would not function. I tore down the dash and removed the bracket. the box I broke was the RFA module (remote function actuation). I ordered one from dealer. $182 later I got the part installed yesterday. I had to reprogram the remotes (dealer wanted $110) using a half a cent paperclip and 30 seconds of my time. as soon as it was installed I figured what the hay and replaced my lamp fuse.....Blam!!! all my lights work great.

    Here is what I found. the RFA module controls the lights the same way the RAP (retained accessory power module) would. It was most likely shorted on the inside and causing power to the lights all the time......Finally I have repaired all the issues that allowed me to get this truck for a steal!!! $250 and 20 hours, repaired leaking trans/transfer case leak, repaired lights, repaired broken shock tower......Some days I love being able to do all I can thanks all for the help....

  7. #7


    that is awesome! Thanks for posting the findings!
    2003 K2500 Sububan 6.0L w/Quadrasteer
    190,000 + miles


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