Headlight Gremlin

Noticed a strange issue tonight when driving my '87 928.

With the engine running the pop up headlights will not deploy.

When the engine is off I can turn on the headlights by turning the ignition key to the pre-start position....they pop up fully lit.

However, as soon as I start the engine the headlights go out, while remaining in the up position (unless turned off).

I did this several time to verify and got the same results over and over.

My main mechanic suggested that I start by replacing the headlight relay switch, however I thought I would check here also to see if anyone had a suggestion/thought or suggestion on this issue.

I almost never drive it a night, but I see no reason why this is happening, as all system appear functional…just not at the proper time!

(moved from technical library to technical discussion)

I think your mechanic may be right but I am not sure.
My first thought was that the run circuit dose not have power to your light module but the accessory circuit dose.
So it could be a fuse or a relay but I am not even sure if there is a different fuse between the two circuits so it may be a relay like he says.
I am sorry that I am not more help as I am at the office and do not have access to the manual.

Brad

928mac;2268 wrote: I think your mechanic may be right but I am not sure.
My first thought was that the run circuit dose not have power to your light module but the accessory circuit dose.
So it could be a fuse or a relay but I am not even sure if there is a different fuse between the two circuits so it may be a relay like he says.
I am sorry that I am not more help as I am at the office and do not have access to the manual.

Brad

Thanks Brad. I ordered the relay this morning as that seems the likely issue. Since the headlights work normally up until I hit the ignition I discounted the fuse. However there may be some sort of short being transmitted at ignition activation. Just guessing now.

Do that but keep in mind your car is of the correct vintage to have a failing ignition switch too... When those fail VERY STRANGE things happen to these cars. It is CRAZY the kind of things that go on when that switch dies. So, you might start the car and then turn the key back (like you are turning the car off) just a little bitty bit and see if that changes anything... That is what you can do for a little while in the early stages of this failure.

Good luck and I hope it is just an easy relay fix!

pcar928fan;2271 wrote: Do that but keep in mind your car is of the correct vintage to have a failing ignition switch too... When those fail VERY STRANGE things happen to these cars. It is CRAZY the kind of things that go on when that switch dies. So, you might start the car and then turn the key back (like you are turning the car off) just a little bitty bit and see if that changes anything... That is what you can do for a little while in the early stages of this failure.

Good luck and I hope it is just an easy relay fix!

Thanks James. Tried your suggestion, but no go. Once the ignition is turned to start the lights go out (stay up) and don't come back on until I recycle the ignition back to pre-start position. Forgot to mention, this vehicle has been a garage queen with collectors and had the best of maintenance (less than 40K miles). Minor problem, but thanks for the help.
Ed