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Engine on:
Headlights don’t go up using stalk.
headlights don’t go up using twilight.
Engine off:
Headlights go up and down perfectly.
Anyone ever come across this condition? Normally I would say it’s a headlight control module, but the fact they work with the engine off is throwing a twist in this.
Do you have ANY DTCs listed in the DIC? Please read them and post up what is there in ALL the modules.
I don't usually recommend this kind of troubleshooting BUT, see if it may work. Disconnect the battery for a few minutes. Reconnect it and Read Your DTCs again using the DIC. If you have ANY that pop up, clear ALL of them and then see if the head lights work properly. Sounds like a logic issue in the BCM. If YOU STILL HAVE ISSUES, Read the DTCs and Post what shows up again.
Has your BCM ever gotten WET? I would check to see if the passenger's foot well carpets are wet or damp OR if there is any moisture in that area. The BCM can cause ALL SORTS OF CRAZY THINGS TO HAPPEN if it gets wet or damp or has been wetted in the past!!!
Do you have ANY DTCs listed in the DIC? Please read them and post up what is there in ALL the modules.
I don't usually recommend this kind of troubleshooting BUT, see if it may work. Disconnect the battery for a few minutes. Reconnect it and Read Your DTCs again using the DIC. If you have ANY that pop up, clear ALL of them and then see if the head lights work properly. Sounds like a logic issue in the BCM. If YOU STILL HAVE ISSUES, Read the DTCs and Post what shows up again.
Has your BCM ever gotten WET? I would check to see if the passenger's foot well carpets are wet or damp OR if there is any moisture in that area. The BCM can cause ALL SORTS OF CRAZY THINGS TO HAPPEN if it gets wet or damp or has been wetted in the past!!!
Bill
No codes in the DIC. BCM never wet. Passenger floor dry. I’ll try to disconnect the battery.
Do you have ANY DTCs listed in the DIC? Please read them and post up what is there in ALL the modules.
I don't usually recommend this kind of troubleshooting BUT, see if it may work. Disconnect the battery for a few minutes. Reconnect it and Read Your DTCs again using the DIC. If you have ANY that pop up, clear ALL of them and then see if the head lights work properly. Sounds like a logic issue in the BCM. If YOU STILL HAVE ISSUES, Read the DTCs and Post what shows up again.
Has your BCM ever gotten WET? I would check to see if the passenger's foot well carpets are wet or damp OR if there is any moisture in that area. The BCM can cause ALL SORTS OF CRAZY THINGS TO HAPPEN if it gets wet or damp or has been wetted in the past!!!
Bill
unhooked the batter. No change. No codes. I have a headlight control module on order. Hopefully that’s it. Cant be the stalk of the twilight doesn’t work either.
Here is the information I used to fix my headlights on my 2003 Z06. Lights went on using twilight sentinal and MFS. The doors would not go up or down. After diagnosing each wire, it was the ground wire in my case. The ground was not connected to ground (aka broken). In your case, test the black, white, dk green, and orange wires with the car running and shut off and lights on and off. You need to rule out that your ground isn't getting power when the engine is running. Then verify white gets power with MFS on, dk green with MFS off, I believe orange is always powered.
Here is the information I used to fix my headlights on my 2003 Z06. Lights went on using twilight sentinal and MFS. The doors would not go up or down. After diagnosing each wire, it was the ground wire in my case. The ground was not connected to ground (aka broken). In your case, test the black, white, dk green, and orange wires with the car running and shut off and lights on and off. You need to rule out that your ground isn't getting power when the engine is running. Then verify white gets power with MFS on, dk green with MFS off, I believe orange is always powered.
ok. Thanks. I’ll give this a look tomorrow and report back.
Haven’t seen too many photos of the headlight control module on this forum, so here is one. electrical connectors all look good. No visible water intrusion. No signs of corrosion. Hoping it’s just a bad module.
On the back of the module is a sealant that seals the entire module case. It has been well known to shrink and separate from the sides of the case. Thats where the moisture gets in. Pull it off the mounting location and inspect. Please let us know what you find.
On the back of the module is a sealant that seals the entire module case. It has been well known to shrink and separate from the sides of the case. Thats where the moisture gets in. Pull it off the mounting location and inspect. Please let us know what you find.
BC
will do. Hoping this will also fix my battery draw issue as well.
YES,, That module has been the cause of battery draw issues on numerous C5s. If the module is warm to the touch when the car is in Sleep Mode, its most likely causing some abnormal current draw.
YES,, That module has been the cause of battery draw issues on numerous C5s. If the module is warm to the touch when the car is in Sleep Mode, its most likely causing some abnormal current draw.
just checked. The module is cold. But the battery draw issue started almost the exact same time as the headlight issue. I’d be shocked if they aren’t related. New (used AES) module will be here Tuesday. Will report back then.
its either the module or the stalk. But the fact that the stalk works perfectly of the engine is off, leads me to believe the issue has to be upstream. All other grounds look good. No other electrical issues. No codes. Battery fully charges and new.
Last edited by vettedays; Mar 6, 2022 at 09:50 PM.
New twist on headlight control module?
