Trying to fix my mom’s S80.

Rear fog light(s) are not working. The manual says there’s only rear fog light on the drivers side, but there’s a bulb on the passengers side also. None of them are working.

In the manual: https://volvornt.harte-hanks.com/manuals/2010/2010_S80/2010S80OwnersManual.pdf I can’t find any information regarding any rear fog light fuse.

Things I’ve tried:
- Measuring the voltage at the bulb socket. When the fog lights are off I measure 0.35V and when the fog light switch is on I measure 2V. Could it be a faulty relay?
- Changed bulb
- Check all fuses in engine compartment
- Reseated relay in the baggage compartment (not sure if it’s for the rear fog lights)

 

There's no relay or fuse for the rear fog lamp. There is for the fronts, fuse is #13 in the CEM for the fronts. The rear fog lamp only works with the headlamps on low beam. And I trust the user understands to only turn it on when they can't see/having a hard time seeing the taillights of the cars in front of you due to weather conditions. Use a 12v test lamp to check voltages to bulbs - modern volt ohmeters will give you confusing results - as you have seen.

 

Thanks a lot for taking a look. That’s news for me, I really thought there would be a fuse or a relay. I’m testing with a good bulb, and both me and a Volvo approved dealership has tested the rear fog light, with no results, they said it could be a broken wire, or a blown fuse(which it obviously can’t be). It’s required by law to have the lamp functioning, that’s why I got to fix it, if not it won’t pass “EU-test”.

Do you have any suggestions for troubleshooting steps? I’ll test with another bulb just to be sure, but would be nice to test some other things while I’m there.

Again, thanks for taking a look!

 

Most functions can be activated manually using VIDA. Has your shop tried that? And someone should be able to test for a "broken wire" at the brown/green or white /blue wire (lhd or rhd) at terminal xx (can't read it) on connector 2 at the CEM.