Electrics: Rear Foglight Issue

[SwissXC90]

Do you have your wiring diagram?

(oops, that well-known Volvo wiring diagram resource is no longer available)

[Harley Dave]

...but you obviously downloaded everything for us - didn't you??

Cheers

Dave

[SwissXC90]

The right-hand fog lamp is wired to the right-hand lamp housing connector
The right hand lamp housing is wired to the left-hand lamp housing with a pink wire, and then directly to the REM

Left hand drive vehicles illuminate the left hand rear fog lamp-
Right hand drive illuminate the right hand fog lamp.

Unplug both left and right tail-lamp housing connectors

Look for the pink wire on pin A3 of the tail-lamp. This is the fog lamp.
Tip: A6 has the black wire and is ground. Use the black wire to identify pin 6.

Pin A3 should have +12V on it when the fog lamp is switched on, and on both left and right taillight connectors.

Pin A3 then goes to pin B4 of the REM

If you have continuity along the pink wire, then suspect a bad ground on the fog lamp itself, or a bad relay in the REM

[john langrick]

Thanks for this Swiss, my thought also that it is probably a relay.

If the rem is the same as mine which is my 03, the rem hides behind the cover on left wall in the boot. Many of the relays are difficult to see let alone remove.

It may be helpful yo dave if you could identify the relay responsible for the fog light unit of this MY.

I found my faulty relay by swapping them around with same part number relay on another circuit. My problem was that although the break lights worked, ithey always indicated blown bulb. Replacement relays are readily available on eBay,

The Haynes manual I have does not cover the layout of my MY XC90 but fixed mine by luck and guesswork..

Cheers john l

[john langrick]

Thanks for this swiss, my thought also that it is probably a relay.

If the rem is the same as mine which is my 03, the rem hides behind the cover on left wall in the boot. Many of the relays are difficult to see rather than remove.

It may be helpful to dave if you could please identify the relay responsible for the fog light unit of this MY.

The Haynes manual I have does not cover the layout of my MY XC90. I had a similar problem where the break lights worked fine, but the break light warning light always came on with the breaks. I shuffled relays with same part number to find where the faulty relay was and the replacement easily sourced from eBay.

Cheers john l

[john langrick]

Hi, this doc may be helpful, you will see the relay suspected is r16.

https://www.google.com/url?q=https:/...CeuDfytWGikGm3

Looks like it may not be too difficult to access. See p 10

Hope this helps

John l

[gmonag]

It is not difficult to access the REM. Just remove panels starting at the roof (next to the tailgate hinges) and work round. The bolts holding the side panel are hidden in the tiedown points.

[Dave18050]

Thanks for all this information and help.

I still have not found the fault. My initial thoughts were that it was the loom to the lamp housing, but its not the continuity is good. There is no power when tested with multi meter.


I returned to the UK over Christmas and during my long drive through France, I encountered some fog. I was playing with the fog light button on the off chance that it would work. And it did!!! several times. seemed to be when it warmed up (not sure if this is possible). However, it has now given up working again.


Having tested all the wires which could be exposed to the elements, I will test the Relay next by swapping around as suggested. My thoughts are that it is either a short or the Relay has packed in.

Thanks again, brilliant information.

[Phaeton]

Is the switch easily swapped out? assuming you don't have to sell your first born to acquire one

[Dave18050]

Removed relay and swapped it with Break Light relay. Fog Light worked and Break light did not. Problem found.

Swapped relays back and gave Fog Light relay a good tapping too with a screw driver handle before putting back. Relay and Fog Light now work a treat!!! Must have been a sticky relay. Problem solved ( I will order a new one just in case).

Thanks again for help and support certainly saved me a few quid.