ternandes

iTrader: (7)

OK, guys... we have an 87 Firebird and and 88 GTA, both of which use the headlight control module that mounts on the firewall next to the brake booster.

The 87 was the initial project. When we had difficulty with the headlights, and traced it to the module, we found that rapping the module would get it to work, but only temporarily. Sooner or later, it would stop working properly. So, we swapped in the module from the 88, and all problems disappeared.

I am now researching parts and other info for restoring the 88, and I learned to my horror that it is nearly impossible to find this part new, and if you can find it, it is a $300 part. Now it is possible to obtain the module as a used part; there's a place that refurbishes them and sells them for $60.

In addition to the risks associated with buying such a part used, I am sure that supply will dry up eventually... that's why I decided to try and fabricate a replacement. After looking at the repair manual schematic, I reasoned that it would likely be simple enough to just build something with the necessary relay(s) to replace the OEM part. I'm sure that some would regard this as a 'hack job', and it would not please the judges at car shows... AND...

Something in the schematic bothered me -- while it clearly showed the relay(s), it did not specify what else was in there. It just shows a block with connections to it.


After research, I learned that this particular system uses 2-wire motors, and the module performs the following tasks:

• when the headlight switch is turned on, it applies power to the headlight motors, to make them pop the headlights up
• when the headlights reach the end of their travel, the module senses increased current demand because the motors are pushing against the 'stops'
• At this point, the module removes power from the motors to keep them from overloading
• when the light switch is turned off, the polarity of the motors is reversed and applied, and the headlights are retracted
• again, at the end of travel, power is removed when resistance to the motors is sensed

SO, I decided to open up the defective module, as it seemed to be a matter of prying with a screwdriver. The case opened with little difficulty. Inside, I found a circuit board, with chips, diodes, and a couple of transistors. This is evidently the logic circuitry that does all the decision making. There is a single relay in the center of the board, and this is the part that reverses polarity, on command from the board.

There is some heat warpage on the clear plastic cover on the relay. Owing to the fact that tapping the module with a screwdriver handle would get things working, I am assuming that the relay, which is the only moving part, is what has failed here.

The relay is made by Omron, and the part # is MY4-02-US 12VDC. I have only found it at one source: California Radios Plus, $13 plus $7 shipping. There is a replacement part made by Omron that is sold by many, including Mouser Electronics, and it is cheaper than the original part. The problem is that it has flat terminals on it, and the original has pins that are soldered to the circuit board. I assume that if you were a patient sort, you could modify the relay and/or the board to accept the replacement, which is only $6 plus shipping. The reason I mention this is because it appears that eventually Cal Radios will likely run out of their stock, which I assume they cannot replenish.

I am going to play with this a little, and if I can repair the module successfully, I will let you all know.

ternandes

iTrader: (7)

UPDATE -- sometimes procrastination pays off. Just for grins, I plugged the module into the GTA just to see for myself that the relay was not right.

In fact, the relay seemed to be OK... yet the lights only worked intermittently. I played with the loose board while turning the lights on and off, and noticed that the relay sometimes clicked when I moved the board.

A close inspection finally revealed the problem: There are two clusters of pins, one for each of the two wiring harness connectors. Since my vision is not what it used to be, even with my glasses, I had missed noticing that some of the pins had broken solder joints. Once I took a close look, I could see cracks when I wiggled the pins.

It looked as if they were 'cold' solder joints, with barely enough solder. I took a soldering iron and some rosin core solder to them, and now the module works fine.

I think I remember seeing somewhere where somebody 'reconditions' the modules -- and this guy mentioned cold solder joints.

In any case, my module is working like new. Anyone wanting help with this, give me a holler. It beats the hell out of $300 for a new one, or $65 for a used one.

Stephen

iTrader: (12)

I swapped my 87 GTA one out for a 89 GTA one, for the same reason. Sometimes worked, sometimes didn't, or a tap on the box would "fix" it.

I never did anything with the 87 box & now my 89 box has started doing the same thing. I usually look for speed bumps or pacement dips/transitions, to avoid having to get out of the car, to do the tap thing.

I'll try resoldering my 89 one, as I have no idea where my 87 one has walked off to. Been a few years since I did the swap between them.

HCR13

iTrader: (5)

yeah, mine had died a while back, turns out one of the wires inside the relay inside the module had burned off, and was loose, so over bumps on the road it would work and sometimes it wouldn't. I opened up the module and fixed (soldered) the problem and it has been working great ever since!

KrisW

iTrader: (5)

OK, I'm bringing this one back from the dead since my search put it up near the top.

I have two (one 88 and one 89) that both need this module fix. Anyone got any pictures of what I should be looking for inside? I will take the covers off and see what is in there soon and see if I can find what you guys are talking about.

Thanks for the help, either way, as just reading the descriptions is giving me hope!

jimmymac1969

Who can i buy the rebuilt module from???
Please let me know maybe a phone number?
Jim 856-213-8879
jimmymac1969@yahoo.com

blackformula350

I opened mine up, but I cannot see where any thing isn't soldered down. Should I just go through and apply more solder on the bottom where everything is already soldered? My left headlight will no go up,motor is good as I wired it up to the driver side wiring harness.

KrisW

iTrader: (5)

It seems from all of my reading that you should inspect those solder joints with a magnifying glass to see if they are cracked or not.

I opened mine up on the 88 and found that one of the little transistors inside was burned in half! I put the one from the 89 (the REAL project car) on to my 88 (the daily driver) and the headlights started going up and down again. I am very happy about that. I'm just one motor away from being squared away on the 88, but now the 89 needs everything hahaahah.

Base91

iTrader: (1)

If you can't see anything wrong maybe it's because nothing is wrong! maybe the problem is somewhere else. I was convinced mine was bad, opened it up and checked it over. With a magnifying glass because my eyes aren't what they used to be either. As I couldn't see anything to fix I put it back together and back in the car. I found a corroded ground wire tucked up just above the battery. That was my head light issue.
That being said I was told by an electrical engineer that 90% of 'electrical' failures are mechanical failures like described above. Good Luck.

blackformula350

Is there a fuse for the headlights?

blackformula350

I am about to my wits end messing with this headlight. Is there a fuse under the dash that deals with the lights? I cannot find the problem, motor is good, relay on firewall is good. Could not find any bad ground wires. I don't know what else there is too check.

tstak

Any answers to your problem? Replaced passenger motor last summer. Just unbagged car a month ago and same motor (new one) crapped out again. After inspecting I noticed 2 of 3 screws on gear box came loose and gears weren't grabbing which damaged gear. Anyway, got new one back on and now, out of nowhere, I have no juice to that connector. All motors work on driver side plug.

blackformula350

Still no luck, thinking about running wires from the driver side.

tstak

Removed and opened control module off firewall. Circuit board, relay look flawless w/ no indication of damage. When I was removing bad motor, I forgot to unplug it first. I thought I heard a jolt when my wrench made contact w/ some of the many obstructions around lamp motor? Thought I was hearing **** until now. So is there fuses for the motors as well as the control mod or what? Did I blow part of module that controls right side motor? I guess it's off to the boneyard for a control mod...

blackformula350

Let me know if that fixes your passenger headlight, if so I am off to the junk yard as well.

tstak

Boneyard near me has a Fiero and Buick Reatta. I'm going to assume that it should be easy to find if used all the way til 02. From what I found, models w/ this module are as follows -
GM part #16525685

Buick: Reatta (1990-1992)
Olds: Toronado/Trofeo (1990-1992)
Pontiac: Firebird (1990-2002), Sunbird (1990-1994)

So if I'm in luck, you may be as well seeing that you have a '90.

blackformula350

I know it has only been a day but any luck?

tstak

Called boneyard and Reatta is a '90 and has module. If we'd stop getting rain I'd go today... Weather's suppose to be nice Monday so my plan is to stop home after work to grab bird and take it w/ so I can swap mods and check while I'm there. Calling another yard that's closer because I'd rather have mod from '02 bird if possible.

tstak

Control module is not my problem. Swapped to another firebird. It works fine. Also, just realized my test light was shot and grabbed new one today. Your to orange wires running into mod box should be hot. My pass side is not. So I'm going through the spaghetti now.... And now a few hours later - the only 2 orange wires (which both run from control mod and into firewall and I'm assuming should both be hot) are the only 2 orange coming through the interior side of firewall. Again, 1 hot 1 not. Seems they both run to a pair of fuse links but those are hot (I could be wrong)??!!! Only thing left to do is unwrap these clusters of wires under the dash but I'm done for the night. It would be great if there was someone on this site that was willing to shed some light on this.

topkick21

I have a 1990 trans am I just picked up and when i turn the ignition forward and start the car my headights come up and on without the switch and the switch will not turn them off they close when the ignition is turn off, can anyone tell me the fix and correct operation of these pop up lights? thanks

tstak

I'd start by pulling headlight switch out to see if previous owner ran wires elsewhere instead of replacing blown switch? It's never surprising what some people are capable of.

blackformula350

Tstak thanks for your info, I will check my orange wires tonight. Do you happen to have a fuse diagram for under the dash, my cover is MIA and no luck browsing online.

tstak

Yeah, let me know if both orange are hot going into mod. If so we have 2 different probs. Hopefully they are and that sheds light on my prob and you'll know you your power stops there. As for fuse box diagram (or cover), Idk if I ever had that. Bought this car in 97 so... There definitely separate sources for each motor and that would mean 2 fuses in box. I don't have a single blown fuse in mine. If I knew if the 2 connecting fusible links next to fuse box and were for motors that could help me. I found and printed out a wiring schematic for headlight doors which shows 2 links but not sure if it's is for my car. It's on this site. When I'm at computer I can post link. On phone right now. Maybe you can make sense of it.

tstak

I may have posted this "quoted" message twice. Oops.

blackformula350

I decided to take another look at my problem a few hours ago. Called my brother who is a mechanic asking about fuses for the headlights. He pulls up info about the Convenience Center under the dash right of the steering wheel. Should be two fuses with orange wires going to each. One fuse for each headlight. To help locate the Convenience Center he said to turn on the hazard lights and track down the clicking sound under the dash. The fuses should be right around the clicking sound. To do a quick check on the fuses he said I could take my voltmeter and check the volts on the orange wires on the headlight module.

The other thing he told me about was to mess with the Headlight Control Module. You will need 2 jumper wires, I fashioned some out of paper clips.

1. Unplug the 4 (four) pin connect from the Headlight Module.

2. Using your jumper wires connect terminal A to terminal D. Then connect terminal B to terminal C.

3. Turn on your ignition, then turn on your headlights.

A. If you see the passenger side headlight come up you have a bad headlight module.

B. If the headlight does not come up you need to start checking your wiring as something is wrong. I am assuming you need to trace the wires from the module back and look for problems.



Now I did the wire jump from the pigtail to the module and my headlight did come up. So apparently I need a new module. I checked it over a few weeks ago and everything looked fine and dandy. So if someone could enlighten me how to repair one please post something up. I even went through and resoldered both connecters on the circuit board with no help.

I did try to check the volts on the orange, key on, headlights on, plugged in the red probe into one of the orange wires, and then touched a good to my knowledge ground with the black probe. All I got was either 0.00, 0.01, or rarely 0.02. I have no idea about how to use a voltmeter so if I did it wrong someone please tell me the right way.

blackformula350

I fixed my problem, turns out it was a fuse under the dash that blew. Didn't have a fifteen on hand so I found a 20 and put in its place. Both headlights are now working beautifully. I have included pictures of location and fuses. Its just right under the dash right of the steering wheel. Look straight up. Labeled HDLP for each fuse. The black box pulls straight out from right to left, just wiggle it. The fuses are right above it.

tstak

I was going to post the same picture!. Fuse in, headlights good! Thanks for all of the input. Much appreciated!

blackformula350

My headlights seem like they are out of sync.

horvathjon

to i have to remove trim to find that fuse?

geoff jaymes

iTrader: (1)

I have been so frustrated with even trying to get my headlight control module off of my firewall to inspect it. I can not seem to get it loose off the firewall.

zs&tas

Hi guys hope you can help me ! my lights work fine, but the buckets only go up not down, if i manual wind down and turn lights on they go up as normal. turn lights off the y stay up ???????
where do i look first ?
thanks
Anthony

geoff jaymes

iTrader: (1)

If anyone has an easy way to remove the headlight control module, feel free to chime in.

tstak

Unplug both plugs and it slides out of bracket towards driver side.

chrisvanguitar5

Bringing this back I am having major problems with my headlights I got the passenger side one working but the drivers motor I took out and it may need replacement when I got it all back together neither headlight went up or down.... I cannot find the headlight fuses and before I decide the module is pooched I am gunna replace those fuses, I also resauldered the back of the board or added some more saulder at least... headlights light up but I have to crank em by hand? It doesn't seem like I have those fuses I can't find em any where, help?

Thanks

Chris

racerbvd

Thanks to you guys, I figured out it was my module that was bad too, and was lucky enough to have a Speedo repair shop (that also works on cool vintage cars, there was a 55 Chevy, 60s GTO & Dodge Lil Red Express truck when I dropped off the module) that was fixing the speedo cluster from our 968, so I knew he cold solder, and I am very happy to report, we now have another source to fix these modules for us..
http://www.speedometerservices.com/

Bobby Suth

iTrader: (2)

my lights go up fine also,but not down.they worked fine in another bird I had that got rearended.this modual they are talking about is on the drivers side firewall,around the fuel pump relay?Sorta sounds to me like the trouble

lonsal

iTrader: (2)

Check the taillight fuse.

Lon

89 formula TPI

hey all, i am having trouble getting the plastic housing off the relay in the center of the circuit board. any tips? any one have a schematic of the circuit board or any info on ordering a new relay?

BobTransAm

I just ordered a reconditioned headlight control module for $125 from:

www.top-downsolutions.com

This was after my mechanic had touched the solder joints of my board with a hot iron without luck.

Someone else report that tapping his board caused the lights to move suggesting a bad relay on the board and replaced the relay (soldering required) in 2009 with one from:

The relay is made by Omron, and the part # is MY4-02-US 12VDC.
I have only found it at one source: California Radios Plus, $13 plus $7 shipping.
There is a replacement part made by Omron that is sold by many,
including Mouser Electronics, and it is cheaper than the original
part. The problem is that it has flat terminals on it, and the original
has pins that are soldered to the circuit board. I assume that if you
were a patient sort, you could modify the relay and/or the board to
accept the replacement, which is only $6 plus shipping.

ikeepitreelz

hello guys.. yes i know this is an old thread but i am trying to stay alive…i lost my wife and kid and i am not looking for people to feel sorry for me. ive owned this GTA for about 22 years and want to get it up and running again. A problem i have i s a-battery drain issue. when i plug the battery in i hear the drivers side headlight motor "click" could it be the motor or the relay? the headlights go up and down normally no issues what so ever. thank you for your help.

BobTransAm

I think it likely is the headlight control module (or its relay) is flaky. Remember that the headlight motor mechanism does not have any limit switches.

Instead the board detects the increase in current draw when the motor stops (up or down) and shuts off power.

ikeepitreelz

Thanks for the reply . I was thinking the same as these motors just that and the brain would be the module. i wasnt too sure. i might open it tomorrow and check for anything needing re-soldering. they are too pricey for me to buy right now and the used ones will probably croak within 2 years.

Drew

iTrader: (58)

If the headlights are in any position other than completely down, when you connect the battery, the module will automatically try to run the headlights down. So if you have any slop in the linkage, or the clutch pellets in the motors, you'll get a short noise.

JonnyThrice

Does anyone know if the module from 4th gen firebirds will work? They seem similar

ikeepitreelz

I've seen them both and they look too alike. I looked up the part numbers and they are different. not sure what the difference is.

1986-1989 Pontiac F body Headlight Control Module -$472.74 GM (16523917) same part # including for the Fieros and the Corvettes.

1990-2002 Pontiac F body Headlight Control Module- $216.46 - GM (16525685)

Drew

iTrader: (58)

You can Google for headlight module interchange and read some of the contradicting info. There are a pile of part numbers, and at least a few of the modules are not interchangeable. Best bet is to look up the part number you need, and then use Google to figure out which applications also used that part number, and any superseded part numbers. Plenty of GM dealers have the parts database online. http://www.gmpartswiki.com has many P&I catalogs databased, you can search by part number and see which books the part is listed in.
http://oemcats.com/ has databases of part numbers that sellers have available (NOS) and if you search a part number there, you can usually find older or newer part numbers for parts that will interchange.

GtaAustin

Hope everyone is doing okay and enjoying this new season with their f-bodies. I have a 1988 Firebird Trans am GTA which I just did some research and found that my control module is also the issue. I opened it up and found a broken wire, so I rewired it and connected to the car. I got the driver side to got up once and then the module started to smoke. It was burning one of the pins on the module. But like everyone else on here, I tapped the relay for the control module to work... I don't know where to go next really. I am going to test the relay to see if the relay is burned inside if not I need to start looking for a new mechanical relay.

ikeepitreelz

I am thinking the box itself has a short and thats why it went bad in the first place? here is a link to a video where the guy dianoses the module. makes me wonder if you made the video his channel name is austin lol.


here is arepair on another one should be similar to our year cars since the 90-92 are different. video doesnt explain though.


last thing, so u dont hack up the harness is you can get one maybe from a guy in south jersey, he lists a lot of things on craigs. his name is eric. Called him up and he has a module for sale he just has to find it. let me know if your intrested.

zacharyhorn

iTrader: (1)

I went to the junkyard and bought 3. None worked. I just want to cruise at night.

zacharyhorn

iTrader: (1)

Thank you. I might be interested. I have three in the garage. Nothing worked. Lights come on but both lights won’t pop. I’m at a loss here.