RĒzĒ

I fixed my hvac unit because the screen was dim, and when I went to test the unit before putting it back together I accidentally plugged it in the wrong way

Not too much seemed to happen, but now my headlights will not open/close and the dash lights will not come on when I turned the headlights on. The headlights and dash lights do still work however. I tested what fuses I could think of (the left/right light actuator fuses seem to be ok) and they seemed to be fine, but I didnt' know if there is anything else I should look for before turning my car over to the stealership to have the problem diagnosed.

Thanks

P.S. on the bright side my hvac unit is nice and bright now lol

dgrant3830

I didn't think that connector would allow it to be plugged in backwards. You must have really worked hard to force it. I'm willing to place a guess that you messed up the BCM. No matter how it happened, the lesson here for all is that if the connector doesn't want to go on, its probably not the right way.

RĒzĒ

We'll see the problem is not that I jammed it in, it's that I connected it before putting the circuit board back into the hvac casing (which has the plastic that keys the direction) So it was more a matter of me being lazy/in a rush to test it. Either way lesson learned.

RĒzĒ

btw if the bcm is messed up is that an expensive replacement? and is it something that an average tinkerer can do himself?

Thanks

dgrant3830

I'm going to suggest a trip to the dealer as they have a tech2 scan tool which is needed in this case. If anything was burned up, it will be able to help figure out what. If the BCM was damaged, you must use a tech2 to install a new one as the car will not even start without properly programming it.
Let's back up to the basics first. Have you pulled the codes yet?

RĒzĒ

Well I did go through the codes after I did this, but there were a lot of codes that were irrelevant, so I reset them in hopes of seeing what new codes would come up. So far today here's the codes I currently have:

28-TCS - Traction Control System
C1225 RF Excessive Wheel Speed Variation

40-BCM -Body Control Module
B2583 LF Turn Signal Monitor Circuit (Short to Voltage)

B0-RFA - Remote Function Actuation
U1096 Loss of Communication with IPC
U1064 Loss of Communication with BCM
U1016 Loss of Communication with PCM

Turn signal is no biggie, there's a buld out i need to replace... Not sure what's up with the other codes, but nothing has come up with any serious issues regarding the bcm

dgrant3830

I think you should send a PM to Bill Curlee. He normally posts in the Tech section but has a better handle on the electrical aspects than I do therefore its worth your time to talk to him. Have you gone through every fuse?

c5streak

Make sure you check fuses #3 &#4, both 10 amp, in the under hood fuse panel.

RĒzĒ

OK thanks for the info. I didnt' go through every fuse yet, but I will tonight. I just went through the ones I thought were relevant including #3 & 4 which are the left right headlight motors.

Bill Curlee

Check the fuses. Then,,if the problem still exist, clear ALL the old codes and then recheck what DTCs reappear and post them. That way we will have a better idea what went south.

As for BCM replacement,,,,there is a BCM to PCM sync procedure that you can preform but, you will need to either go to a dealer or find some one with a TECH II to program the new BCM to reprogram any RPO options that you have. If there are NO RPO codes to reprogram, you would be good to go with just a resync.

Clear the DTCs and then repost any new codes that show up.

BC

rws.1

Do you have rear tail lights or are they dead too?
I recently repaired trailer light backwards and shorted the system.
The headlights would turn on but the motors did not raise or lower them... each motor has a separate fuse... but they were ok
I then realized the rear tail lights were also not working
I checked that fuse and it was blown.
When i replaced the rear tail light fuse, the headlights motors immediately sprang to life.....

RĒzĒ

Awesome, thanks man. that was exactly my problem. all seems good now!

dgrant3830

Which fuse was blown so the rest of us will know?

RĒzĒ

#6 in the passenger side foot well

The symptoms of this fuse being blown are:
- tail lights non-functioning (the obvious problem, but I didn't even realize this until rws mentioned it)
- dash backlights non-functioning when headlights are turned on
- headlights will not go up or down.

Too bad the service manual did not even mention the #6 fuse when diagnosing the headlight problem. I would have figured this out a long time ago hehe.