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91 Headlight Control Module

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Old Jun 22, 2015 | 09:36 AM
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Default 91 Headlight Control Module

I had sudden failure on both sides to pop up. Per FSM diagnosis, it is the module. Since it is NLA, like many parts for our cars, who is the best vendor for it or does it matter? I see they are reproduction parts and the prices go from $140 to $200. Not sure. Any advice? TIA
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Old Jun 22, 2015 | 09:42 AM
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Originally Posted by aklim
I had sudden failure on both sides to pop up. Per FSM diagnosis, it is the module. Since it is NLA, like many parts for our cars, who is the best vendor for it or does it matter? I see they are reproduction parts and the prices go from $140 to $200. Not sure. Any advice? TIA
Did you try to clean the connections.
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Old Jun 22, 2015 | 09:51 AM
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Originally Posted by antfarmer2
Did you try to clean the connections.
Twice. No go still. They even have dielectric grease as a last ditch attempt.
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Old Jun 22, 2015 | 09:58 AM
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Originally Posted by aklim
Twice. No go still. They even have dielectric grease as a last ditch attempt.
And the fuse is good and clean......never replaced one but would see if you could get one local in case you have trouble.
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Old Jun 22, 2015 | 09:59 AM
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It gets power just that it won't send out power.
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Old Jun 22, 2015 | 10:41 AM
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Originally Posted by aklim
It gets power just that it won't send out power.
Sounds like you found it.
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Old Jun 22, 2015 | 11:34 AM
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Yes i did. Now to find a module at a decent price and not a used one or reproduction if possible
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Old Jun 22, 2015 | 12:59 PM
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Not sure if they are interchangeable but the C5 uses one that looks identical. Maybe there is a way to CrossRef them?

http://www.ebay.com/itm/like/131525239819?lpid=82&chn=ps
http://www.ebay.com/bhp/corvette-headlight-module
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Old Jun 26, 2015 | 05:56 PM
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Originally Posted by We Gone
Not sure if they are interchangeable but the C5 uses one that looks identical. Maybe there is a way to CrossRef them?

1997 2004 Corvette C5 Headlight Control Module Flip Up Headlights | eBay

http://www.ebay.com/bhp/corvette-headlight-module
It probably is. I decided to buy a NOS item http://www.ebay.com/itm/141698561428?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
A couple things I noticed. I fawked up. It was for a Buick Reatta, Pontiac Fiero, Firebird and Sunbird. I noticed it after it was on the way. However, a contract is a contract is a contract so I had to hope it works or dispose it myself. Bought it for $180 plus $9.99 shipping. Got it today.

Hooked it up and it worked. I got the headlights working despite my stupidity.

2 things I noticed. 1 is that there are no felt pads to cushion it from the wheelwell. I took the old ones and put glue and it works. Next is there are some brass inserts that the attachment screws go into. Fortunately, the old ones were recoverable and I made that work.

Now I have lights. HAPPY again.
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Old Jun 26, 2015 | 06:19 PM
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Great info.
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Old Jun 26, 2015 | 06:41 PM
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Anyone know how good the reproduction units are?
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Old Jun 27, 2015 | 12:48 PM
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OK. Now we have an issue. I smelled something burned and pulled apart the old module. Stink of burnt circuits was VERY strong. Looked at it and 3 points around the board were burned. Also there was some water.

Looks to me like water contamination and since most of us know water and electricity don't get along, maybe we need to take out the module and seal the edges shut so no water gets in?
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Old Jun 27, 2015 | 05:52 PM
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What a bummer.
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Old Jun 28, 2015 | 09:49 AM
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can you post pictures of what you found?
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Old Jun 28, 2015 | 10:15 AM
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Water droplets present when opened
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Old Jun 28, 2015 | 10:32 AM
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I would have to agree to the water intrusion theory as the culprit.

Looks like both transistors need replacing (BUZ10), two zener diodes (Z1, Z2) Z3 appears ok, C1 appears compromised and Q5 appears to be split.

So far about 15 dollars worth of parts it the board doesn't need repairs. If you can find the parts.

Could you flip it over and post a picture?
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Old Jun 28, 2015 | 10:46 AM
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It would also be interesting to note the replacement part circuit board number.

Would you be willing to take the new one you have apart and post a picture of the board?

The part number of the board (16509737-4), which is written on the bottom of the board itself, crosses to the 3rd gen firebirds. Is this the first time this part has been replaced?
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Old Jun 28, 2015 | 11:25 AM
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Little more digging revealed there are multiple control boards that do a similar function but not necessarily work in different applications.

http://www.fiero.nl/cgi-bin/fiero/sh...tyle=printable

Seems that some of these boards are wired internally to be different for specific applications.

Curious if anyone might have the board number from a C5 Corvette control module?
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Old Jun 28, 2015 | 03:00 PM
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What does the other side of the board look like? The transistors are available(just looked them up) not sure about the the diodes since I cant see the number. I'd scrub the board with lacquer thinner and old toothbrush then use a DMM to check the components. I used to repair electronics and this should be an easy fix. Can always use it as a backup or sell as repaired.
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Old Jun 28, 2015 | 08:01 PM
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Originally Posted by kg4fku
I would have to agree to the water intrusion theory as the culprit.

Looks like both transistors need replacing (BUZ10), two zener diodes (Z1, Z2) Z3 appears ok, C1 appears compromised and Q5 appears to be split.

So far about 15 dollars worth of parts it the board doesn't need repairs. If you can find the parts.

Could you flip it over and post a picture?
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