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Need Help Diagnosing Headlight Problem

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Old Jul 31, 2016 | 10:01 PM
  #1  
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Default Need Help Diagnosing Headlight Problem

Hi All,

I posted a thread about this problem a month ago but got no response, and I've searched the forum and can find nothing similar to the problem I am experiencing.

While driving in the day time, the headlights on my '02 Z06 will (infrequently) quickly open half-way and then close, all in less than a second in time. The best way to describe it is a "flutter" or like a blink of an eye. This isn't an everyday occurrence but can happen once or twice a week.

Today, it happened five times within a minute. Afterwards, I turned on and off the lights and it didn't happen again. The first time today it happened as I accelerated onto the freeway, then again when I changed gears, then when I put in the clutch to shift into 5th gear, and then when the car was decelerating to exit the freeway. Also, a couple of nights ago, the left headlight did not open, but after I turned the lights off and on again, everything worked OK. The multi-function switch seems to be working correctly.

Does this sound like it could be caused by a malfunction of the headlamp control module? The module is getting 12v to it, but could it cause the headlights to open and close without any input from the multi-function switch?

Thanks for any suggestions or insight you can provide to help me solve this problem.

Rod
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Old Aug 1, 2016 | 11:43 AM
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That's a tough call. Take the control module out and see if the back of the module is cracked or separated. I do not know how much a new module is but, pick a place to start.

BC
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Old Aug 1, 2016 | 12:01 PM
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Default shot in the dark

Does the Z06 have the twilight sentinel option? If so, you might make sure it's disabled.
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Old Aug 1, 2016 | 12:14 PM
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Thanks for everyone's help. No, my Z06 didn't come with the twilight sentinel and I don't think it was even an option for the Z06.

As a start, I will remove the headlamp control module and pull it apart to see if there is any sign of an internal problem or overheated connections. I'll source a good deal on another module as a backup or replacement.

I'll let you know what I find out.

Rod
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Old Aug 9, 2016 | 12:47 PM
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UPDATE: Three days ago I replaced the headlamp control module with a good working used unit and so far so good. The problem has not occurred after I replaced the module. It was an easy job once I found out where it was located.

The rear cover of the original module was starting to separate, but when I removed the circuit board I couldn't see any obvious signs of corrosion or loose connections. The problem must be somewhere in the electronics.

Thanks again and I appreciate all your help. The Corvette Forum is such a great resource.

Rod
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Old Aug 11, 2016 | 11:39 PM
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Originally Posted by HotrodZ06
UPDATE: Three days ago I replaced the headlamp control module with a good working used unit and so far so good. The problem has not occurred after I replaced the module. It was an easy job once I found out where it was located.

The rear cover of the original module was starting to separate, but when I removed the circuit board I couldn't see any obvious signs of corrosion or loose connections. The problem must be somewhere in the electronics.

Thanks again and I appreciate all your help. The Corvette Forum is such a great resource.

Rod
Rod,, Good job.. Can you post some detailed pics of what you saw on the old module board??
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Old Aug 12, 2016 | 12:09 PM
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Originally Posted by Bill Curlee
Rod,, Good job.. Can you post some detailed pics of what you saw on the old module board??
Bill,

Here are some pics of the old module board that I replaced. The black circular discoloration on the back side of the board was caused by a strip of the rubber adhesive used to glue the rear plastic plate to the housing. The only thing I could see when I removed the module was that a corner of the rear plate had lifted slightly from the housing.

Again, thanks for your help.

Rod






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Old Aug 13, 2016 | 10:05 AM
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Originally Posted by HotrodZ06
Bill,

Here are some pics of the old module board that I replaced. The black circular discoloration on the back side of the board was caused by a strip of the rubber adhesive used to glue the rear plastic plate to the housing. The only thing I could see when I removed the module was that a corner of the rear plate had lifted slightly from the housing.

Again, thanks for your help.

Rod
That circuit board is not environmentally protected, except for the rear cover plate being sealed. If the cover plate seal is compromised, moisture (either water OR from humidity) can easily get in. That relay is a 4pdt and is not sealed either. That's a lot of contacts that can fail.
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