I'm slowly making my way through the new MY90 I picked up for (cheap). Lots of neglected items, but nothing seems to serious yet.

One of the things that seemed strange, that I've never experienced before is a rather erratic set of headlights. When they turn on they come up and then the motor just continues to cycle. It's basically doing a full rotation and will continue to go until I shut off the lights.

Thoughts?

Here's a video of the problem:

http://www.youtube.com/watch?v=kS0fxoYqFn8

 

Someone put the wrong headlight motor in it - a '90 would not normally do this... can you check the part number of the motor

Alan

 

I have another 928'er whi is local to me here in FL who is having a similar problem in a 78. When he turns the car off (without turning the headlight switch off first ) the headlights go down then up then down a couple of times. I'm not sure if they ever stop without turning the switch off. Any ideas Alan?

 

On my 82 it was the relay and also the diode on the motor!

 

what else is connected to that relay? wondering if the whole thing went bad, or just the part that controls the motor. I'll pull the number off the motor. it looks like it's been in there a while. then again, there's really no way for me to tell.

 

Doesn't it sense an increase in load and parks it? If you know the answer mark, please explain.

Thanks

 

My $.02: my switch was at fault. But then again all those switches are all connected to each other in the most exciting wiring job ever in a dashboard... it could be one of the other switches which is messing with the voltage. Check your current.

 

Sorry, forgot to mention that I had the exact same problem except my headlights would sometimes turn themselves on, then start going up and down, up and down, until I cycled the switch.

 

I would suspect the semi-circular switch in the headlight motor which signals when headlights are in up position.

I'm also puzzled by motor behaviour in your video. I'm pretty sure that for at least MY88 onwards the motor changes direction to lower headlights - in earlier cars the motor goes in single direction. So maybe the motor is at fault?

 

Tell us what the part number on the motor is ?

Earlier than '87 the headlight motor continues to rotate in the same direction - half a cycle for up and the next half cycle for down. after '87 the motor does a helf cycle up and to go down reverses direction. In this mode it is not designed to cycle beyond the up position and should not physically be able to do so unless it is misaligned. That it can do so suggests its been swapped to an earlier motor - this does not work - the two are totaly incompatible electrically. The other posibiility is that the relay has a stuck contact although on the motor that seems to be rare - your video suggests this is possible simply because the lights do come on at the top of the cycle - this is normally controlled by the limit switch.

For <'87 cars that do this its likely the limit switches or diodes in the motor that have failed so it doesn't know it got to the top and just keeps going...

Alan

 

This always happens to me when I leave the headlights up after manually extending them, and then I use the switch to turn the lights on. They will cycle up and down indefinately. Try extending them manually, and then lower them manually- see if that solves the problem....Once lowered manually, actuate the switch and it should be normal. Let me know if it works for you...

Thanks,
Mason

 

This may well be true for you - but it should not work this way - something is not adjusted correctly for this to make a difference...

 

It's happened to me several times on at least 2 different cars. If he tries it, it might work. I guess we'll see! Maybe the manual override function won't allow the headlight motor to function properly unless it's fully retracted manually first.

 

+1

 

Unfortunately a '90 doesn't have any diodes... and even if the switch on the motor failed - on a '90 the pods would not go back down again...

Alan