Porsche Enthusiasts Club Forum

Hi folks, sorry to bring this up as i know it's an oft asked question but i am off on a trip on Fri and headlights are a must.

I've looked over threads discussing the light issues etc but need a little clarification.

Car is a 90 s4 auto, uk car.

The headlights work when raised manually but you can hear a motor running under the right hand lamp constantly (adjuster motor? Electric at this age?).

The lights lower on their own but only raise half way and seem to stick, then needs manually raised a little and they pop up.

Bar turns correct way towards the front of the car and bolt is tight, c clips present.

The relay i disassembled and cleaned. Assuming as the lights work, that's ok?

The motor i disassembled and cleaned the tracks.

The only things left are the bar not located correctly on the spindle or the switch? Would a bad switch give the above symptoms?

If the lights are up and the switch is in the on position, where should the bar be located?


Thanks in advance, if we could nail this I'd be a very happy boy.

Olie

Hi Olie

The general rule is >>> its ALWAYS the relay...lol

Borrow one from another 928 owner, swap it in and see...

I did everything you did on my S2 , and eventually someone told me about that massive relay...new one and it all worked perfectly again...

But borrow one if you can to check it is that first...as they are expensive...

All the best Brett

It was rusty in parts before i cleaned it up.

Might just bite the bullet and buy one.

Thanks Brett.

The constant running is electric height adjuster motor. All 928s from 89 on were electric not hydraulic.

There is a comparator circuit inside the adjuster unit that cuts motor when voltage set by pot rotated by motor balances voltage set at 4 position switch by driver's seat.

Sounds like your comparator has failed. You can either buy new unit from OPC or used, or repair circuit board. It's laughably easy to remove/test the couple of transistors on circuit board compared with modern surface mounted components!it could also be dirty track on potentiometer that is sending duff signal to comparator, fixed by squirt of contact cleaner like Servisol. A good example of how many parts on a 928 can be repaired back to as new.

The adjuster can be removed after removing headlight in raised position. It's just bolted to headlight yolk. I have done this repair but can't remember whether I needed any access by removing wheel well liner.