Brett Jenkins

When I turn my high beams on, the driver's side headlamp goes out completely. I've replaced the bulb and checked all the fuses, relays and all seems fine. Any other electrical connections or components that could cause this?

AO

If it's only the driver's side, then I don't think it could be anything except either the bulb, or the wiring between the bulb and the relay as teh relay switched both lights on the same circuit. Have you checked for 12V at the bulb?

Alan

There are seperate fuses for L/R & Low/High headlamps - swap the L&R for high beam - any difference. Don't rely on eyeballing the fuses - sometimes they blow but look good.
check the power at the fuse socket also (the top connection is the fuse input).

If not this then I'd suspect its the wiring somewhere in between fuse & headlamp - check that the Central Electric plugs are well seated and locked in - find the central electric plug connections for the High breams out L and checlk for voltage there (probe in through the back of the plug) , check for voltage at the headlamp connector (hope it isn't failing in between)

You don't have 100W/130W bulbs in there do you?

Alan

AO

Ahhh yes. Forgot about the separate fuses. That's a more likely culprit.

Jim bailey - 928 International

Porsche thought it was a good idea to have the headlights on separate fuses just in case you were traveling 150 MPH at night and had a short , only one light goes out ! Traveling 220 ft /second in the dark could get exciting

tv

I had this problem and it was the $100+ relay.

Jim bailey - 928 International

Correct if power is not going to both fuses then ....Relay Relay Relay ...

mjensen

I had the sme problem but low beam on my 84 928S, the wiring inside the driver's fender, where the light pivots up and down was cracked/broken. Soldered and heat shrinked the wire and all is good...

m21sniper

This happened to me too. I just had some corrosion at the relay mount, and a 30 second cleanup job fixed me up good.

Brett Jenkins

Is the relay mount near the PS reservoir?

Mrmerlin

Hi Bro you should look very carefully at the wire harness as it comes out of the headlight chances are the wire is broken due to mis routing or rubbing against something, the headlight relay is on the bottom far right side of the relay board in the pass foot well it is the big one .
Also to check is the harness just next to the headligjht motor look at the linkage you might find the harness is getting caught in the linkage , Good luck, Stan

Brett Jenkins

well, DS high beam just started working, so I'm guessing wiring or ground somewhere. Too frickin cold to track it down right now, though.

Alan

I'd guess its the wiring somewhere that flexes with the headlight up/down movement - when it warms up! - take off the headlight pod cover & try flexing the connector wiring with the headlight on - see if its intermittent... you may be able to figure out whats going on. You may need to pull the wheel/wheel well liner & splash shield to take a closer look underneath.... Its pretty clear what goes where - check all the wiring...

Could still be a ground that varies with temperature - but grounds usually exhibit dimming & generally wierd behavior - not simple on-off intermittent....

Good luck... with the weather & car...

Alan

michaelathome

Bump for an OLD thread.

I have this problem as well, actually passenger side hi beam doesnt work.

I looked at all of the fuses,
- 38 + 39 (main dip up/down?)
- left the fuse/chart in the car I think 25/26 for the main headlamps, pretty much looked at all the fuses from 20 and up, tested them as well al were good. I have not checked the lamp/bulb continuity.

Checked a total of about 20 fuses, all good and replaced the bulbs. So what I have left is the relay or a ground I guess.

So where is the ground (photo please) and does anyone have a working relay I can test, if so please bring it AND your car to Frenzy 11

Michael

Alan

Guys if only one side is non-functional - its not the relay (some confusing posts above that don't match these single sided symptoms) - the relay has only one set of contacts for high beam and one set for low beam. So don't pull the relay to test it for this issue - you'd be wasting your time!

Make sure the fuses are good for the mode you need www.928gt.com has fuse/relay charts if yours is missing...

The bulb is by far the most likely failure point for a single filament (or the 4 L & R) not working. Next is the fuse, next is the connector wiring near the bulb - it may get flexed in operation & over time break - next is the wiring under the pod in the fender (including all the way back to the ground point (GP I on the front clip next to the ignition final stages - in clear view for LHS and GP II on fender wall just in front of radiator for RHS).

Ground point failures on the headlights often exhibit as dim operation of both bulb filaments.

But always if the other of the L/R pair works correctly - you know the switch, relay and wiring in between is good...

Alan