BCM Problem?

[Blue Bowtie]

2000 Jimmy, 262, Auto, 4WD, 4 Dr.

Truck was being driven at night. Headlights were on via automatic control (headlight switch off). Driver turned on high beams and immediately lost exterior and I/P lighting. "SECURITY" lamp turned on immediately.

Driver reports that the turn signals have been operating oddly recently and the dual-flasher would operate with the turn signals and hazard flashers off (typical failing switch).

Battery is at 13.4V.

Headlights still operate via the manual switch. All multi-funtions switch features seem to operate - turn signals, hazard, wiper/washer, but high beam indicator does not illuminate. No way to test cruise currently.

Engine starts and runs for about two seconds (typical PassLock problem).

Remotes do not function and I cannot program remotes to operate the locks. All underhood an interior fuses test good.

Generic code scanner shows no DTCs. My "good" scanner is out for upgrade.

Interior/courtesy lightng does not operae via the jamb switches. Underhood light does not operate.

SECURITY lamp turns on with KOEO, times out and turns off, then turns back on after about three seconds. SECURITY lamp will remain on with the key removed and doors closed.

Does this sound like a BCM failure, or possibly a loss of power to the BCM? The main connector on the underside of the BCM appears so be intact. Any hints?

[MT-2500]

Originally Posted by Blue Bowtie

2000 Jimmy, 262, Auto, 4WD, 4 Dr.

Truck was being driven at night. Headlights were on via automatic control (headlight switch off). Driver turned on high beams and immediately lost exterior and I/P lighting. "SECURITY" lamp turned on immediately.

Driver reports that the turn signals have been operating oddly recently and the dual-flasher would operate with the turn signals and hazard flashers off (typical failing switch).

Battery is at 13.4V.

Headlights still operate via the manual switch. All multi-funtions switch features seem to operate - turn signals, hazard, wiper/washer, but high beam indicator does not illuminate. No way to test cruise currently.

Engine starts and runs for about two seconds (typical PassLock problem).

Remotes do not function and I cannot program remotes to operate the locks. All underhood an interior fuses test good.

Generic code scanner shows no DTCs. My "good" scanner is out for upgrade.

Interior/courtesy lightng does not operae via the jamb switches. Underhood light does not operate.

SECURITY lamp turns on with KOEO, times out and turns off, then turns back on after about three seconds. SECURITY lamp will remain on with the key removed and doors closed.

Does this sound like a BCM failure, or possibly a loss of power to the BCM? The main connector on the underside of the BCM appears so be intact. Any hints?

Blue Bowtie
Any add on remote start stuff?
Any jump starting?
Try the auto learn procedure.
Key on for 10 minutes until the security light goes out.
Then key off for 5 seconds then 2 more key on for 10 minutes until light goes and off for 5 seconds.
If that does not get it disconnect the battery and engine and body pcm and plug them back in an and try the relearn again.
Also try the door lock and unlock with ign key and spray door lock with penetrating oil. And check door hinge wiring.
If no help or no start.
You will need to get the B body codes and U communication codes.
Good Luck and let us know how it goes.
MT

[Blue Bowtie]

No remote start or alarm - Unaltered vehicle, even down to the stock radio.

Standard factory remotes and wiring. No jump starting AFAIK. Battery has been charged, however, and positive connection was marginal but cleaned.

I'll try the relearn. Thanks for the help. I'll keep you posted. One of thee days my Modus will arrive (perhaps I shouldn't have paid in advance?)

[blazes9395]

I think you need your "good" scanner on this soon. MT's plan of attack is what I would start with. This sounds like there could have maybe been some voltage spike(or short), causing problems. I personally think you may have a wiring issue to the BCM, but of course getting a good scanner on there will give you a better idea of whats going on.

[ponchonutty]

This sounds like a simular problem on a 99 Jimmy. What also happened was it would fail to start and the theft light would come on. The weird thing was that the light would stay on even when the key was off. Ended up being a short in the BCM harness