So, I have a 1994 850 Sportwagon. A couple of weeks ago, my left side headlight went dim as I was driving at night. I didn't have a chance to deal with it till yesterday. Here's what I have discovered.

1) When the headlights are on normal mode, the low beam bulb is dim, like it is when the high beams are on. I know that this isn't the bulb, because I purchased a new H4 9006 bulb, and it does the same thing.
2) When the headlights are in high beam mode, the left side goes out entirely. I know this isn't a problem with the high beam bulb, because I switched it with the one from the right side - which works fine - and the problem remained.
3) When the headlights are on, the high beam indicator on the dash partially illuminates. It didn't do this until the headlight problem started.
4) When I turn the high beams on, the "bulb out" indicator comes on.

Anybody have any suggestions?

 

So, here's my suggestions:

See attached diagrams; I've circled possible suspects but before you dig into the detail, check the following items:

1. Poor ground for the left low beam.
2. Dirty connector for the left low beam. Remove the connector and clean; a can of electrical contact cleaner & air duster is helpful.
3. Trace the wire for left low beam as much as you can to see if there's an exposed/frayed section.

If above visual inspections turn out OK, then go after the suspects. From what I see on the diagram, it could be one of the following:

1. Faulty Low/High/Turn signal switch (dirty/loose connections): Inspect & clean.
2. Faulty headlight switch: Inspect, clean & replace if necessary.
3. Faulty Headlight relay in the CEU (Central Electrical Unit = Fuse box in the engine compartment): Inspect, clean & replace if necessary.

Without actually taking a look & testing it by myself, electrical problem is a headache. It may or may not be due to a known common problem. See if you can receive others' replies.

P.S: Is your wagon dual bulb or single for low & high beams?


JPN

Attachment deleted.

 

Bad ground???
I could imagine the headlight relay or socket but that doesn't explain
the high beam indicator. Maybe a ground connection that is common
to both the left headlight and high beam indicator circuit?

 

Those suggestions all make ten kinds of sense... however, work has prevented me from having any time to investigate them yet. Hopefully sometime in the next couple days.
And JPN, my wagon is dual bulb.

 

Sometimes Volvos give you strange problems...

Try tapping/knocking suspected components to see if something happens...


JPN