Question: dome light ground location?

[Durascrap02]

Have you checked to see if the ground is actually activating at the BCM pin for the interior lights? Did you do a continuity check on the wire from the BCM to the relay?

no i didnt but i will now that you say that. you'll have to forgive me im not the best electrician, thanks i will check that out! if i knew how to put pics on here i would show you guys all the corrosion under my dash

 

[heymccall]

The white wire to the lamps becomes grounded when the BCM commands the CTSY LAMP relay to close.
The orange wire is the 12V supply from the INADV PWR relay. You know the INADV PWR relay is good and functional, as you have power to the lamps.

I'd swap out the CTSY Lamp relay with the EXT ILLUM relay as a test, but I suspect the CTSY lamp relay to be bad, meaning a swap will leave you with no ext illumination.

The panel (in the attached image) is located behind the Park Brake pedal.

 

[Chevy1925]

The white wire to the lamps becomes grounded when the BCM commands the CTSY LAMP relay to close.
The orange wire is the 12V supply from the INADV PWR relay. You know the INADV PWR relay is good and functional, as you have power to the lamps.

I'd swap out the CTSY Lamp relay with the EXT ILLUM relay as a test, but I suspect the CTSY lamp relay to be bad, meaning a swap will leave you with no ext illumination.

The panel (in the attached image) is located behind the Park Brake pedal.

yup but swapping those two will do you no good if the ctsy relay is bad as it will no longer send power to the lights. granted you can test the lights to see if they have power once you do this but dont expect the lights to turn on.

If you do switch the two and the lights still have power at their sockets, then go back to the BCM and on the middle connector (C2 connector), find the gray/black stripe wire (A3 hole on that connector) and either back probe it with another wire or pull it from the connector and ground the wire. If your lights come on, you BCM is bad. if they dont, you have a broken wire somewhere and your gunna need a test light to start testing powered areas to narrow it down.

so heres the simple verson. switch relays and check for power at lights

if no power at light: repolace original ctsy relay and re-test (should be fixed)

if power at lights: ground out gray/black stripe on C2 connector on BCM

If lights come on: BCM is bad

If lights dont come on: broken wire some where, will need further testing (highly unlikely but can happen)

got the wiring schematic to save as well. hope this gets ya fixed up!!!

 

[heymccall]

yup but swapping those two will do you no good if the ctsy relay is bad as it will no longer send power to the lights. granted you can test the lights to see if they have power once you do this but dont expect the lights to turn on.

If you do switch the two and the lights still have power at their sockets, then go back to the BCM and on the middle connector (C2 connector), find the gray/black stripe wire (A3 hole on that connector) and either back probe it with another wire or pull it from the connector and ground the wire. If your lights come on, you BCM is bad. if they dont, you have a broken wire somewhere and your gunna need a test light to start testing powered areas to narrow it down.

so heres the simple verson. switch relays and check for power at lights

if no power at light: repolace original ctsy relay and re-test (should be fixed)

if power at lights: ground out gray/black stripe on C2 connector on BCM

If lights come on: BCM is bad

If lights dont come on: broken wire some where, will need further testing (highly unlikely but can happen)

got the wiring schematic to save as well. hope this gets ya fixed up!!!

He already verified power, so the CTSY Lamp relay is the ground control, so it needs checked or swapped.

 

[Durascrap02]

thanks guys i will give her a whirl!!

 

[Chevy1925]

He already verified power, so the CTSY Lamp relay is the ground control, so it needs checked or swapped.

right but if you swap the two relays you told him to do and the ctsy relay is indeed bad, he will no longer have power to the lights but the ground will work so it will seem it fixed nothing unless you check for power again at the lights. he gets power now at the lights, switch relays and if the ctsy is bad, no more power to lights

 

[Durascrap02]

yup but swapping those two will do you no good if the ctsy relay is bad as it will no longer send power to the lights. granted you can test the lights to see if they have power once you do this but dont expect the lights to turn on.

If you do switch the two and the lights still have power at their sockets, then go back to the BCM and on the middle connector (C2 connector), find the gray/black stripe wire (A3 hole on that connector) and either back probe it with another wire or pull it from the connector and ground the wire. If your lights come on, you BCM is bad. if they dont, you have a broken wire somewhere and your gunna need a test light to start testing powered areas to narrow it down.

so heres the simple verson. switch relays and check for power at lights

if no power at light: repolace original ctsy relay and re-test (should be fixed)

if power at lights: ground out gray/black stripe on C2 connector on BCM

If lights come on: BCM is bad

If lights dont come on: broken wire some where, will need further testing (highly unlikely but can happen)

got the wiring schematic to save as well. hope this gets ya fixed up!!!

well i did like you said and swapped the relays had power, so relay is good. pulled the c2 plug from BCM and grounded the wire gray/black wire and the lights turned on so theres my answer. bcm, so my question is how much does a BCM cost or is it not worth spending the money for a dome light?

 

[Chevy1925]

and opening either door does not make a difference right? try keeping that wire ground out and see if the lights turn off when you shut the door (may take a min or two for the delay to shut them off)

if that turns them off, leave the gray/black stripe wire unplugged and jsut splice it into the dark blue wire (spot A8) on the C1 connector (its one of the outer two but i dont remember which one that is but A8 will have a dark blue wire) using, what i prefer, a scotch lock. should work just like factory untill the BCM really goes under but those things aint cheap

 

[Durascrap02]

what i did was pulled the plug and just touched a wire that i grounded to the dome/ground wire and they turned on my door was open when i did this. so i will try doing that same thing with the doors shut and dimmer switch off, and i will see what happens when i open the passenger door and shut it. i'll let u no, btw thanks for the help its always nice having somebody that knows whats going on!

 

[Chevy1925]

haha its no prob. i know these 01-02s pretty damn well cause im always trying new things and tryin to figure it out. thing that really interest me is alot of stuff is ground triggered. ive reallyonly worked with switched power so i find these trucks interesting to learn how they did what they did. granted i dont know everything about them, give me a schematic and some time and ill figure the issue out though.

 

[Durascrap02]

no they dont shut off so splicing it to inadvertent A8 probably wont work huh?

 

[heymccall]

Not to pic a nit, but I asked to have the EXT ILLUM relay (for the parking lamps) swapped with the CTSY Lamp relay.

The INADV Power relay feeds power to the courtesy lamps, and voltage was verified, so we don't touch that one as the OP verified power at the lamps.

So, we try a replacement CTSY Lamp relay to check the ground controlling circuit.

If the CTSY Lamp relay were bad, we'd now have courtesy lamps, but no exterior park.


That makes this statement false...

right but if you swap the two relays you told him to do and the ctsy relay is indeed bad, he will no longer have power to the lights but the ground will work so it will seem it fixed nothing unless you check for power again at the lights. he gets power now at the lights, switch relays and if the ctsy is bad, no more power to lights

The only way that statement would be true is if "INADV PWR" were swapped with "CTSY Lamp"

We merely wanted "EXT ILLUM" and "CTSY Lamp" swapped, which would only affect courtesy ground, and NOT courtesy hot.

 

[Durascrap02]

i swapped the inadv pwr with the ctsy lamp because i didnt see a ext illum plugged in to that relay center, so am i missing a relay? wait no because on the cover with the diagram it doesnt show an EXT ILLUM relay.

 

[heymccall]

 

[Durascrap02]

i seen that earlier when u posted it im sayin that mine has 3 relays down there INADV, CTSY, and PRK LMP the only 2 that i could switch is CTSY with INADV, i did that and no change, because the PRK isnt the same relay. i pulled the whole thing out and there isnt even any wires going to those spots.

 

[heymccall]

i seen that earlier when u posted it im sayin that mine has 3 relays down there INADV, CTSY, and PRK LMP the only 2 that i could switch is CTSY with INADV, i did that and no change, because the PRK isnt the same relay. i pulled the whole thing out and there isnt even any wires going to those spots.

Alright then, my suggestion didn't help there, BUT grounding the gray w/bk wire did turn on the lamps, so the relays are good.

The BCM is suspect, BUT the dome override can still be at fault.

Unplug the dimmer switch assembly. Do the courtesy lights work (they shouldn't)?
Now, with the switch unplugged, ground the Purple wire. Do the courtesy lamps now work (they should if the dimmer/ override switch is bad)?


BTW, another thing to remember/ think about, is that on one of my trucks here, the dome override button had no effect at all unless the key was on.

 

[Chevy1925]

Not to pic a nit, but I asked to have the EXT ILLUM relay (for the parking lamps) swapped with the CTSY Lamp relay.

The INADV Power relay feeds power to the courtesy lamps, and voltage was verified, so we don't touch that one as the OP verified power at the lamps.

So, we try a replacement CTSY Lamp relay to check the ground controlling circuit.

If the CTSY Lamp relay were bad, we'd now have courtesy lamps, but no exterior park.


That makes this statement false...



The only way that statement would be true is if "INADV PWR" were swapped with "CTSY Lamp"

We merely wanted "EXT ILLUM" and "CTSY Lamp" swapped, which would only affect courtesy ground, and NOT courtesy hot.

right, i kept thinkin you were talkin about the inadv pwr relay as the lower trims didnt have the ext illum features/relay. either way would work to check

 

[Chevy1925]

Alright then, my suggestion didn't help there, BUT grounding the gray w/bk wire did turn on the lamps, so the relays are good.

The BCM is suspect, BUT the dome override can still be at fault.

Unplug the dimmer switch assembly. Do the courtesy lights work (they shouldn't)?
Now, with the switch unplugged, ground the Purple wire. Do the courtesy lamps now work (they should if the dimmer/ override switch is bad)?


BTW, another thing to remember/ think about, is that on one of my trucks here, the dome override button had no effect at all unless the key was on.

purple wire is the dome light defeat, meaning it will keep the dome lights off. dark blue/white stripe wire is the one your lookin for. grounding that one should turn the dome light on.

durascrap, did you try opening and shuttin the door yet?

 

[Durascrap02]

Alright then, my suggestion didn't help there, BUT grounding the gray w/bk wire did turn on the lamps, so the relays are good.

The BCM is suspect, BUT the dome override can still be at fault.

Unplug the dimmer switch assembly. Do the courtesy lights work (they shouldn't)?
Now, with the switch unplugged, ground the Purple wire. Do the courtesy lamps now work (they should if the dimmer/ override switch is bad)?


BTW, another thing to remember/ think about, is that on one of my trucks here, the dome override button had no effect at all unless the key was on.

tried it with key on and off nothin! so i guess that means the bcm is bad. when i pulled the bcm out last i did notice a good crack on the outside plastic case that holds the actual module, looks like somebody tried prying it open and cracked it dont no though. thanks for the help guys, much appreciated!!!

 

[Chevy1925]

tried it with key on and off nothin! so i guess that means the bcm is bad. when i pulled the bcm out last i did notice a good crack on the outside plastic case that holds the actual module, looks like somebody tried prying it open and cracked it dont no though. thanks for the help guys, much appreciated!!!

which wire? be sure it was the dark blue/white stripe. the purple one is the wrong one.