Rear fog lights
 

Ok i give up, warning on dash says rear fog light fail, neither work. however turn the switch on and the warning goes. Fuses as far as i see are good...next?

Check the actual bulbs? Assuming they're good then clean the connectors? Maybe a bad earth if the warning is acting funny.

Does the telltale light on the dash work when switch is on?

Hi, yes bulbs are good, rear lights work normally, just fogs, and yes the switch telltale light too...

Not really sure of my way round on these canbus systems..

Do you have a towing socket (or is there evidence that one may have been fitted and removed)?

If there is/or was, look around the for extra connectors around the tailgate area or behind the light clusters. There is an factory socket for towbar electrics but not installs use it.

Operationally, on a RH drive vehicle, usually only the RH rear fog works.

Hi, no towbar, never has had one..

The next place I'd check is the REM (Rear Electronic Module). I'm not sure which relay is for the rear fog, perhaps Google will have the answer to that question. Also while you're looking at the REM, did you check the rear fog fuse on the REM?

easy fix mate!

swap the relay in the boot (REM) with the reverse lights relay (assuming your reverse lights work)

hopefully they should then work and the reverse lights fail indicating a shagged relay

the second column of relays swap the 4th one up (reverse) with the 6th one up (fogs)

Hey,

I had the same problem a few weeks back. Bulb was good, fuse was good but as soon as i turned on the rear fog light, i got a warning.

After measuring all of it, it turned out that the lower rear light unit was broken. There was a small piece missing on the circuit, causing the fog light not to get any power.

Very strange as it always used to work, so i guess it burned through at some point.

If i recall correctly the bridge in the attached pic was missing.

Bought a 2nd hand unit off eBay for 50euros or so from a same age V70 to prevent any color difference. Works fine now...