2004 XC70 intermittent left/right headlight failure

aaronlife · Post by **aaronlife** » 27 Feb 2024, 08:10

I noticed this past week that the headlights started going out while driving. If I wait, they will come back on, sometime quickly, or sometimes it takes a little longer, and I've stopped waiting. I discovered if I switch the headlights off and then back on they work again. When they go out, I get a multiple bulb failure warning on the dash. Any ideas? Inspection is this week (March 1). I was thinking of leaving the headlights off, because they work fine as soon as they are turned on, high and low beams, but I am hoping to figure this out. Was thinking maybe it's a relay issue? I thought that bumps in the road triggered the lights to go off, and then on, but then noticed it happened on a smooth road. Thanks for any advice!

Post by **vtl** » 27 Feb 2024, 09:11

Oxidation/heat damage in sockets. I fixed one temporarily by wiggling the contacts with a small screwdriver, but eventually need to replace the harnesses. They are cheap, like $10-15 on Amazon. Need to cut and crimp/solder.

aaronlife · Post by **aaronlife** » 27 Feb 2024, 09:20

thanks i'll check that out

aaronlife · Post by **aaronlife** » 27 Feb 2024, 09:24

fyi, both left and right go out simultaneously, and the high and low go out at the same time

Post by **vtl** » 27 Feb 2024, 09:35

aaronlife wrote: ↑27 Feb 2024, 09:24 fyi, both left and right go out simultaneously, and the high and low go out at the same time

All 4 bulbs are controlled by separate fuses. Low and high beams likely have a separate relays. Both low and high going out at the same time is very unlikely.

How do you verify that both go out? It's either low or high beams are on at the same time.

aaronlife · Post by **aaronlife** » 27 Feb 2024, 09:49

switching between high low on the stalk while my wife stood in front of the car, she said neither worked. only parking lights stayed on.
i'll have to drive the car tonite and play with it again and verify.

aaronlife · Post by **aaronlife** » 27 Feb 2024, 09:49

the multiple bulb failure warning on the dash is what caught my eye

Post by **vtl** » 27 Feb 2024, 09:56

Trace ground wires from all bulbs, they perhaps joined together at some point and attached to the chassis. Loose connection or wire chewed by rodents may cause all bulbs quitting simultaneously.

aaronlife · Post by **aaronlife** » 27 Feb 2024, 09:57

okedoke thanks

02V70 · Post by **02V70** » 29 Feb 2024, 15:10

I had my high beam relay fail and make both high beams intermittently work. On one of my low beam lights, the plastic on the wiring connected to the lightbulb was coming off and shorting. Wrapping the wire in electrical tape and replacing the lightbulb fixed it. You may also have a blown fuse, but for some reason, I didn't have one.