In running searches on the forum, I've noticed several issues involving headlight activation, but none quite like what I've experienced.

The problem is both headlights are stuck in the up position. Other than lowering them manually, the only other way I've found to get them down is to disconnect the battery. The moment it's disconnected, they lower. What's even stranger is they will work properly for a day or so after the battery is reconnected, but will soon stick again in the raised position. There's no grinding noises or actually any noise indicating the headlights are trying to lower.

The problem first started with the twilight sentry turned on. I actually had to turn the headlight switch on and back off to get the lights to turn off after the key was removed when the twilight sentry was on. I turned the twilight sentry off to avoid the potential problem of forgetting the lights were on, but the headlights failed to lower. That's when I began experimenting and tried disconnecting the battery.

My original thought was there was a problem in the "computer" and felt leaving the battery disconnected for enough time to reset the logic settings might do the trick (this works on some Japanese cars). However, the results were as noted above.

I'm all ears if you have any ideas.

Regards, pmcw

 

Not sure what year you have but this may apply.

Twilight Sentinel/Automatic Headlamp Control Not Functioning Correctly or is Inoperative (Reprogram BCM) #03-08-42-012 - (Nov 18, 2003)
Twilight Sentinel/Automatic Headlamp Control Not Functioning Correctly or is Inoperative (Reprogram BCM)
2000-2004 Chevrolet Corvette

with Automatic Headlamp Control (RPO T82)

Condition
Some customers may comment that the twilight sentinel/automatic headlamp control delays turning on/turning off or is inoperative.

Correction
A procedure using the Tech 2® has been developed to reprogram the twilight sentinel feature within the BCM.


Important
The Tech 2® must contain software version 23.006 or later available from Techline® starting October 18, 2003, on the TIS 2000 version TIS 11/2003 data update or later.


Install the Tech 2® to the vehicle and power on.
Build the vehicle from the menu options.
Select "Special Functions" from the menu options.
Select "Twilight Sentinel Reprogram" from the menu options.
When the reprogramming is completed, the twilight sentinel feature should function properly if no other faults are present in the system.

 

Took a second look (listen) and there is a "double thunk" - very light - when I turn the headlight switch to headlights (versus parking lights) and the same noise again when I turn them to off. The noise sounds like it's coming from the headlamp door control unit that I believe is located below the right headlamp.

I guess this means the question is whether the control unit is getting the right signal or if it is bad. Any comments are appreciated.

Regards, pmcw

 

If the headlight bulbs turn "off" but the doors dont close,that eliminates the headlamp switch on the column.Sounds like a faulty headlamp control module below the right headlamp.I have seen them get water in them,and sometimes they have a burning oder when faulty

Make sure that the clunk is not coming from the headlamp motor.If it is,it is possible that you have a stripped gear or a linkage problem.It is possible that the module will not close the headlamps if it does not detected the correct position feedback signal from the motor caused by a stripped gear or skipping linkage

 

Thanks C-5 TECH, What's the best way to check the gears and the linkage.

Regards, pmcw