Dougs951S

I know, I know, there are a zillion threads out there about headlights working fine, but being stuck in the up or down position. Most of the time its the relay, not this time. Basically my headlights were working fine, then today they just refused to go up. I changed the relay with a known good one, still not working. Then I took the motor apart to clean it, still nothing. I took the motor off and attached it to my 84 944, still nothing so aha I thought, bad motor. I swapped in the known good motor from the 84 into the Turbo, that one wont turn either..all current values are normal as measured at the 4 pin connector, its switching the motor on and off correctly. No binding anywhere, although the old motor was getting very hot when it was just sitting there with the ignition on. All new fuses in the 3 relevant places also did not solve the issue, and I know that I wouldnt be getting proper voltage at the 4 pin connector if the rotary switch on the dash somehow went bad, so I really dont know what the issue is now, especially since my perfectly good motor appears to have gone dead randomly, and my known good motor is not working correctly either. swapped it back into the 84, and the motor worked fine. never could get the motor out of the turbo to work in the 84 though, despite swapping relays again as well. Any ideas gentlemen?

JohnKoaWood

Have you rotated the manual **** on the back of the motor to try to manually raise them?

Doing so with the motor connected should (at the point you get the motor off the lower limit switch) cycle them open then closed again automatically.

Try that and report back.

Sounds to me like your linkage in the turbo is jammed, preventing it from cycling... double check all the linkage connections. It could be that one of the pivots on either headlight have moved or jammed up preventing it from cycling.. I just went through the entire headlight setup when we swapped to a turbo nose, and it is entirely possible for it to jam to the point of not working.

Dougs951S

it isnt the linkage being stuck, when I said I couldnt get either the motor to turn in the turbo, I had not hooked them up to the linkage yet, just trying to get them to spin hooked up to the electrical source. they failed to cycle at all, even though the lights turned on and off as they were supposed to and when i put the old motor back into the 84, it worked fine.

JohnKoaWood

Ahhhhh... Will double check the electrical scematics when I get home, and post back later...

Dougs951S

Update: So I think the old motor from the turbo is really borked now because when i put it back into the turbo, it instantly blows fuse number 37 when I turn the lights on. I grabbed the known good motor out of the 84 and swapped it back into the turbo with a new fuse, and erueka, it turns now. The problem is that it will only turn in one direction, meaning that although the electrical values at the 4 pin connector are correct now, and the blue/yellow trigger wire is switching from 0 to 12 volts when the lights are turned on, the motor will not raise the headlights, it only forces them to lower. It doesnt matter if the keys are in the ignition or not, or whether the light switch is in the on or off position, if I plug the 4 pin connector in after manually raising the lights, it will make them go down, and I can only raise them manually. If I want the lights to be raised and stay there, I have to disconnect the motor. This doesnt make any sense to me at all..I hate chasing electrical gremlins. The most confusing thing about this is that, I thought the motor only engaged the "down" position if the switch was also in the closed position? seeing as how the 12 volts is changing which should engage the "up" position, I dont understand why its stuck forcing the lights down.

JohnKoaWood

Ok, on review of the wiring..

I would suggest swapping the light switch, as that is the only junction to be causing fuse 37 to blow.... If swapping light switches doesn't fix it, second would be to clean the contacts in the ignition switch.

I just confirmed on my car the motor only ever turns one way!

Do you get 12v to pin 3 of the connector when the light switch is on?

Dougs951S

what color is pin 3? im pretty sure it has power when the switch is on. i checked it with clarks garage and all the electrical valuea where in spec.

Dougs951S

I did as you said and with the fuse in place and everything set up properly, I tried to manually raise the headlights and at the end of the lower limit switch, the motor did very briefly cycle but it forced the lights down, it didnt cycle them though the up and down cycle. Also, it did this regardless of whether the ignition was on or off, and regardless of the light switch position. I'm baffled...I prefer problems I can fix with a hammer

JohnKoaWood

Well, I know if you turn the **** the wrong way, the motor will impulse the headlights shut. Have you tried to turn the **** the other direction?

I dont have my schematics in front of me, I will have to double check the wiring schematic of the late car I was looking at last night, as it seems to differ from the clarks garage description somewhat IIRC.

I will not be back home till late this evening, but can double check the scematics and report back. IIRC constant power comes in via the bridge connector, the trigger to raise the headlights comes from the light switch (when the key is on), and the trigger to lower the lights is a result of removing power from the raise trigger line and applying it to the lower trigger line (once switched ON it remains on till the switch is turned off, if the keys arent on, and the switch is moved to raise the lights, the trigger to raise is never sent via pin 3, hence my suggestions to replace the light switch then the ignition, either one of which could easily result in a sudden failure). FWIW, the trigger to raise the lights, and the switch to turn on the lights are different switches in the light switch assembly.

I can also snap pictures of the scematic, and highlight the traces on them for the headlight circuit.

If I had to venture a guess, my initital guess is your light switch is faulty, followed by the ignition switch. I believe this because the resuting action is the same using a second motor. The fuse you blew is BEFORE the light switch, on the line running to the raise trigger via the switch, indicating to me the switch is at fault (grounding that power feel rather than passing it through to the raise trigger).

I will follow up with pictures of the schematics either late tonight, or tomorrow!

The NORMAL action for the lights, when the switch and ignition are off, is to fully cycle the lights if you turn the ****, because power is ON to the close trigger for the headlight motor, but because the motor only moves in one direction, a small turn of the **** to raise the lights should be energizing the motor, resulting in a full cycle (fully open, then closed again).. this is the action I observe on EVERY late car I work on.

Dougs951S

I read, and then reread your last post a few times, and at first it seemed very plausible that it was my light switch, but then I went out and messed with it some more, and I made sure I was turning the **** in the raising diretion. after a certain amount of lift, they just cycle closed again. I'm still not convinced its the switch yet because here is the thing, when I have the motor disconnected from the linkage, it seems to operate fine. cycles smoothly as it should when the light switch is turned off, and then on signaling to me that; if hooked up to the mechanism and my understanding of the system is correct, it should simply work and yet it doesnt...so of course that leads me to believe the mechanism is binging somewhere but how...how could the mechanism go from working smoothly and then a few days later be so bound up that it wont work..also, if I raise the lights manually with the fuse out, then put it back in, the lights will of course cycle closed, but the action is smooth...no binding, and i can move the linkage easily by hand with the motor out of the car..I also think that whatever happened to make this all come about also burned out the old motor, so looks like I'll be buying a new one if I want the lights on the 84 to work.

JohnKoaWood

Turning the **** either direction will result in the light raising, but ONLY turning it the direction it normally drives in will result in a full open-close cycle of the lights.

Have you tried turning it the opposite direction to the direction you have been turning it?

If you turn it backwards, it will start to raise, then imediately close the lights again, turn it the "right" way and it should fully cycle the lights. (this seems to be what you are describing)

The close signal is ON no mater what, when teh light switch is in the off position. But the micro switch in the headlight is off when the lights are closed (because of a detent in the wheel inside the motor. If you back the motor up to the point the switch turns on, the **** jumps and the lights are driven closed till the switch is again off.

If you turn the **** in teh correct direction, till the close switch turns on, the motor should drive the lights till the switch again turns off, difference being in this scenario, it is almost a full 360 degrees of motor rotation to reach the detent to turn off the close switch in the motor assembly.

Does this much make sense?

Dougs951S

Yes it makes total sense now. I was not familiar with the method in which the raising mechanism worked, and sort of assumed it had a bi-directional travel, ie it would move one way to raise the lights, and one way to lower them. I realize now that the linking bar simply spins in a 360 degree rotation to cycle the lights..seems simple enough, very typical german engineering. it's 8 am here, so I'll go look at it some more here in a little bit.

ok so i just went and played with it for a second..it seems i cant turn the **** in the opposite direction enough to make it cycle, as it gets tight. something is binding. this is of course, only with the motor bolted to the linkage. I dont understand how it can be binding ( so it seem) in one direction and not the other. I'll try rotating it in that direction with it unhooked and see if i can get it to cycle.

JohnKoaWood

Likely the binding is due to the position the mount is installed in... loosen the bolts, and spin the motor with it connected...

the mount will reposition itself to eliminate the binding...

and yes, I just finished fully adjusting the headlights on my new to me front end!

Dougs951S

Ok so upon further investigation I believe I have discovered the cause of my issue. I connected power to the motor to confirm the direction that it likes to spin, and armed with the knowledge now that the motor indeed spins only one way, i took it off the linkage and spun it as you said and yes, it ran and cycled properly. The reason i found that it wont work hooked up to the linkage is that on the passenger side, the linkage arm is pressing up against one of the hard lines that runs by the radiator...I wish i could be more specific, but I dont know exactly what line it is...it makes sense because i recently had that hard section off the replace the lower rad hose that sits right above the alternator pulley. After finishing that job...thats when the headlights stopped working and im 100% certain that is the cause of my issue...however I cant move that line to make the needed clearance to slip the headlight linkage underneath it..can i move it in a full circle and make it come to rest beneath it by running them in a full circle in the opposite direction that the motor runs in? Is there an easy way to fix this besides taking off that line, getting coolant everywhere, and then having to refill and bleed the coolant system?

JohnKoaWood

All the linkage is held together with C clips, remove them, and you should be able to fit the linkage into the correct position without having to open the cooling system...