Jim Chambers

I have done a search, but found more than I could digest.

Problem: High beams (both) do not light. Low work fine, fogs work fine. When I shift switch to high beam the indicator lights and the aux. driving lights come on but main high beams are dark. When I flash the aux. lights come on but no high beam. I have checked both high fuses and they are good.

I have not checked bulbs yet since it seems both out at once would be unlikely. Where do I look next? Is there a way to bypass relay to check it?
Something with the switch assembly (not sure I want to mess with removing it with air bag in the way)? Ideas?

ZEUS+

It would be wise and easy to check the bulbs first. I have seen both high and lows burnt out many times. With bulbs removed you can test both high and low beam circuit easily with a test light. White wire high beam right, white/black wire high beam left.

the flyin' scotsman

There is a relay, its the large headlight combination one at the right hand side of the fuse/relay panel.

Once you check the bulbs and the presence for voltage at the bulb connectors I'd try swapping the relay into a car that works as should.

Jim Chambers

OK, so much for failing to follow the age-old automotive wisdom.......always check the simplest thing first........even on a 928. Both bulbs show no continuity between the brown and white terminals, good between brown and yellow. Both white and yellow will light a test lamp at the plug.

Off to buy bulbs tomorrow. But, both out at the same time gives me pause. Also, I can't see a break in either filament in the bulb, which is usuallly the case when one is out. I wonder if something "blew" them. Guess I'll find out when I fire up the new bulbs.

the flyin' scotsman

When you say 'both white and yellow will light a test lamp at the plug' that is when you switch from low to high beam seperately?

Jim Chambers

Yes.
I am less than positive that the problem will be totallly solved with new bulbs, but using an ohm meter I have continuity on low filament, none on high. Also, when switched to low beam test light is bright. Then when I switch test light to high plug terminal (still switched to low), I get a very faint glow on the test light. That is a bit worrisome.

Mrmerlin

you might consider the Sylvania Blue lights low beam has a slight blue tint Hi beam is whiter

the flyin' scotsman

I wouldn't worry to much about the test light results for now.

We've confirmed the bulbs are blown and you are getting power to the high beam side of the connector.............as you noted the main high bean aux lights are functional.

The issue I had was the connectors themselves...............the PO had big pwr bulbs that the wiring/connectors couldn't handle after sometime. Frig!!!

Mrmerlin

try to get the original wattage bulbs 55/65 IIRC

Jim Chambers

Off to the parts store tomorrow. Thanks to all. I will report results once I plug in new bulbs. One minor point of interest, one bulb had a plastic locking ring holding it in place. No ring on the other side. Bulb seemed to be a tight fit without it but suppose I should get a lock ring for it.

michaelathome

Sucks that we do not really have a well organized parts service or co-op. I have 3 bulbs in my garage, that are sitting unused. Problem is that it would cost as much to ship them to you as it will cost for you to go and get new.

Michael

Mrmerlin

you try to post a picture of the light housings you may have 2 different securing housings

WallyP

The test light glow may indicate resistance in the ground connection. You might want to clean the ground (MP) for the lights.

Mrmerlin

Wally good catch I missed that point about the test light . Since this is happening it might be wise to remove the front fender liners and inspect the harnesses that run under the headlamps to the chassis holding clips.
Make sure that the harness has extra flex run the lights up and down and inspect the harness for a cut wire and also follow Wallys advice about the ground points.
Its quite possible that the harness is damaged under the headlamp

Jim Chambers

Where is ground for headlamps located? I will explore.

Is there an accessible cavity below the headlight where my missing lock ring could be hiding? Will removal of fender liner get me there?