Topic: BCM

[snaponbob]

I may need a Body Control Module. Recurring issue with the right rear tail light assembly, and it seems there is no voltage signal for the stop/turn lamp from the BCM. Will be calling GM Customer Svc as this happened in warranty and has recurred out of the 3/36 Bumper to Bumper time frame.

Anybody got one?

[2kwk4u]

Have you probed for voltage right at the BCM connector?  Have you tried to just tweak the terminal and/or pin?  If your BCM is crapping out, I'd expect more than just that one symptom.  Hate to see you spend all that money for a new one and still have the same problem.

[snaponbob]

So far, no output from the BCM for the right tail light. I still need to double confirm, but I am sure this ture.

[Sol Asylum]

Do the hazard lights work?

[snaponbob]

Do the hazard lights work?

ALL lighting functions work EXCEPT the circuit to the r.r. brake/turn beams. The bulbs are not bad (swapped them), there are no bround issues, there is just no output for that circuit as measured AT the BCM connector. The only tests left are check AT the BCM pin, and them swap the BCM. Today I will call (what's left of) Saturn and see if a pre-existing condition will qualify the car for additional warranty attention. This is NOT the first tome around  on this issue.

[2kwk4u]

So just to be clear, the rr bright lamp doesn't light EVER, right?  Not even when the Hazard switch is pushed, correct?  i.e. your hazard lights aren't "4-way flashers" but more like 3-way (mind out of the gutter)

[snaponbob]

No brake light, no blinker, and no 4-way. There are two circuits;  the low watt circuit is for running lights and all other high watt outputs are the other circuit. I have running lights.

I have just returned from gathering the G/M p/n, and checked pins A9 (left brake/turn signal) and A12 (right brake/turn signal). These are also the 4 way outputs. A9 energizes, A12 does not. Looking at the GM wiring diagram, it just must be the BCM.

[scanner]

If this circuit has effected past BCMs I wonder if there is short to ground at times.  The BCM has the ability to store DTCs for this, see B3951-02, you'll need a good scantool to see this...  A short to ground could be a current condition too.  That is, if the circuit is shorted low and you back probe for voltage there will not be any or very low, causing it to look like no BCM output.  If you have the terminal tools swap left & right and retest.  If the BCM is toast find out why, they don't just die, something likey killed that channel unless there is some indication of a common problem with the BCM.
Scanner

[SolNut]

My first Kappa had a wrongly routed cable in the RH Wheel Well.  Not sure if this could even be your problem, but checking the cable routing sure can not hurt. 

Good Luck 

Steve