GiDvEtTe84

Hey guys. My 84 Vette has the late C4 headlight upgrade. The module only opens one headlight and the circuit board is kinda burnt by the transistor. I took a module from a 91 Firebird and tried it on there and it doesnt do anything. Can anyone tell me what is different about these modules? I can get the Part #'s if you need. I would like to make it work somehow cause the module is very expensive new. Thanks.

bogus

Try used... I don't see how the Firebird module would work with the mechanics of the C4 headlite.

GiDvEtTe84

I thought it would have worked. Its a 2 wire motor with a worm gear. I am not sure about the headlight switch tho. It may not be sending the same signal to the relay circuit. I wish i could find some schematics on these things.

96_LT4_FE1

I take it the board is accessable, since you mentioned you could see a burnt spot. I'm also assuming it plugged in, but didn't work. I got a relay from a dealer for a headlight motor once that plugged in perfectly(had 6 contacts), but it was actually wired completely incorrect internally, turns out it was the wrong one, so it is possible that they are not compatible even though they plug in.

can you see the curcuit board on the firebird one to note any differences?

Do you play with electronics at all? first thing I would try is look for cold solder joints. Its amazing how many things go bad and that is the only problem.
Second, are the #'s still on the transistors? if so, you may be able to try replacing some components. Its pretty much guess and test, though.

Can the headlights be plugged in separately, and can you swap them to test both lights? (just covering all the bases)

I do know that the compontents between the two models look amazingly similar, but I do not know what parts are the same, if any. Corvette lights do about 180 degrees of motion, whereas the birds do about 90 degrees, but other than that, the operation it pretty similar. What I am unsure of is how the stops work, I haven't looked at my vette close enough to see if it is a simple mechanical stop like a bird, or if its something unusual.

I was just thinking, It could be something stupid like the motors rotating the other way. Did the healights make any noise at all with bird module? (long shot)

Not sure if I'm helpfull at all, »keith

GiDvEtTe84

hey Keith, thanks for your time. just to clarify, my old one is burnt, the new one is not. I will take them apart to see if theres any differences. When i put the firebird one on, the relay makes no noise at all. I will try my multimeter on it to be sure im getting signal from the switch. I may swap some components from the new to the old if they are the same, as you mentioned. The motors do work if i put 12V straight to them. I will update when time permits. Thanks again.

GiDvEtTe84

I've added a couple of pictures to clarify:

Firebird module on left/Corvette module on right



Firebird module closeup:



Corvette module closeup:




I am thinking of swapping the BUZ10 transistor and fuse to the corvette module.

On another note, is it possible to wire a toggle switch directly to the motors and shut it off manually when they reach their extents? This would be a temperary fix but may help until i can do something with the module.

Thanks gurus.

96_LT4_FE1

As you can see, the main relay is wired the same(the schematic is on the cover). But the component layout is slightly different and it appears they may be using a different controlling IC. I don't know how versed you are in electronics(I'm certainly no genious), so if I sound like I'm oversimplifying, no offense is intended. My guess is each of the large transistors is responsible for one light, and I'm sure there are some other matching components that are part of each "side" of the circuit also. It could be any part of it, but I must say that the transistor looks pretty rough. The main IC(the largest chip) is going to be the 'logic circuit' that decides what light moves where, a major transistor failure like that could have easily damaged that too. Just thinking out loud of all the possiblities.
It appears each board uses a different IC, so that would explain the different layouts. I tried looking up the IC online, but didn't find a crossreference. I did find a site called icmaster.com that looked promising, but, to be honest I didn't want to register my email address. I don't know how far you want to take the search up, but you can give that site a shot too. datasheetarchive.com and alldatasheet.com didn't seem to pan out for the IC, though.

Those are very nice closeup shots of the boards. If you could post up the same shot of the backsides of the boards, I may be able to map out a schematic that could explain the differences and maybe a solution could be found to make it compatable. Its a stretch, but you never know.

The vette board almost looks like its been repaired before on the jumper wire. I would tend to buy new components rather than risk the firebird board just yet.
I found the BUZ10 online, but if you can find a local electronics place, that would be better. the site says no minimum order, but I'm sure there is a minium cost. I looked on radio shacks site, but they are becoming less and less helpfull with 'real' electronics parts and I couldn't find it there, at least not under the same name.

On to the switch. Yes, it is possible, -but- I would not recommend it cause, to me, I'd just manually wind the lights all they way up and leave them their till its fixed. Its not worth risking accidentally leaving the switch(or bumping it) and burning up a motor. At the very least I'd use a double pole double throw momentary only switch so they switch would have to to be held in order for it to work. It would be something like this:


After reading all this, I'm sure you can see why most people eventually take the amount of hours it is taking divided by the cost of the part and it often gets depressing how little dollars/hour they are saving.
Thats why you don't see much info around on stuff like this.

although, at the very least, when you got this all figured out and done, you might as well wire up the left light so you can "wink" at people with it.

HTH, »keith

Morley

If the traces on the corvette board are still visable, I'd make a new board and transfer the connectors and other "hard" parts to it, then put new electronics on it. Check this site...if they don't have it, it doesn't exist. http://mouser.com/

GiDvEtTe84

Hey man,

Thanks for all the help. I know i am trying not to go the toggle switch route. I usually order from Mouser.com. I will try to get some pics of the backsides soon.

GiDvEtTe84

More pics:

firebird module:


Corvette module:

mikenfl

I converted my '85 to use an '87-'89 Firebird module instead of the external relays and internal limit switches. (found a tech tip here on CF) I had a few problems and did a little more research. I don't remember what forum/message board I found this on, but the author said he was a parts manager at a GM dealership. Anyway, he said the '87-'89 Firebird module was pn.# 16523917 which was also used on '87-'88 Fiero, '86-'89 Buick Skyhawk, '86-'94 Pontiac Sunbird and '97-'04 Corvettes. I guess the C4 module was different.

GiDvEtTe84

Back to the toggle switch idea.....Could i use 1 SPDT switch and 2 DPDT relays to work both lights? Gonna have to think a bit more on this one.


Heres a spring loaded center off toggle which would help any human error.

http://www.radioshack.com/product/in...entPage=search

How many amps does each headlight draw?

96_LT4_FE1

I'd have to map it out, but I know where you are going, and its posible. then you could use a microswitch to control it even.



A switch like that, rated at 20 amp, I'm confident could handle one light, maybe be both. I would take a wild guess that the lights were 8-10 amps each, but it could be higher. Also, the "stall" amps would spike very high, but I'd just as soon the switch burn up rather than the motor.
Most multimeters go up to 10 amps, so you could measure it if it is below 10.

I have an idea for a self regulating curcuit using a small self resetting breaker, or possibly even a signal flasher, but I have to work out a few kinks. If I think I'm successful, I'll post it.
»keith

CorvAdel

I once bought a used h/lite module from local TA and Camaro shop and it worked on an 88...I don't know if it came off a TA or Camaro...they might be the same. I also bought one as a back-up from a guy who was breaking an 88 Fiero...plugged it in and it worked.
One of the above would be a better option than mucking around with interchanging used parts, unless doing that would be a source of entertainment or academics.

96_LT4_FE1

Thats a good point. Also, a friend of mine mentioned ebay for inexpensive parts.

...but, since I have an irritating and irrational pursuit of solutions, I think I may have a homebrew idea for the bold.

The theory is, bi directional headlight motor, self energizing power circuit triggered by a momentary ground from a switch. The self-reseting breaker(a bulb flasher might work?) should be set for an amperage just over the power needed to startup the lights, but within safe current levels for the circuit capacity. When the breaker opens the circuit, the relays open, and the circuit remains open when the breaker resets.

The circuit could probably be balanced to even do both lights a once. Although the fastest light would enivitably be at 'stall' slightly longer than the slower light. And it is very possible it could be integrated to work with the factory switch, but probably would need altering to do so.

It is essentially the same operation as the module without the precision or low cost(to produce) of the module. I'm thoroughly convinced someone good with basic IC skills could probably build a better setup, but I'm not quite that smart or that motivated.

feel free to poke holes in it, its just a thought.
»keith

GiDvEtTe84

Keith,

You sure are working hard, i appreciate it! I guess i will have to troubleshoot the circuit before I can continue. Maybe i have some other problem here that causes both modulesnot to work.

CorvAdel

Im curious what year the TA was that you got it from.


Thanks to all.

bondouvich@aol.com

Question ,,, how can I wre my 1987 corvette lights to work with my 1988 headlight module?

thank you

Corvette40

I'm using a module pulled from a Pick a Part 91 Firebird in my 88 and it only cost me $15. Mine burned up just like yours. Dyno Don has a 90 Firebird so I pulled his off and tested on my 88, it worked so off to the Pick a Part I went. The 89 and below 3rd Gen modules did not work.

Corvette40

I thought about this but in the end it would be too much work. I did the research and I could get all the parts from Orvac Electronics but testing and the possibility of burning up one of the motors caused me to rethink the issue, why reinvent the wheel? By the way, it was my motor that failed and for some reason burned up one of the IC chips. Strange because the module should have cut power when the overload condition was detected but didn't.

ccrazor

Another zombie revival?? Only 8 years old..