I found a blown bulb (actually, it had shattered in the receptacle, ... it was the "spare" bulb for the rear fog lights) and removed and replaced it with a working spare. Rear fogs come on fine. However, now, the third brake light (in the rear window of a 850 sedan) does not come on. Looked in the manual and did not see a dedicated fuse for that light, and I replaced it wit numerous 1157 and 1156 bulbs but still no illumination. Checked the contacts as well (however I will be checking them again). Going to the junkyard today to see if there is an 850 that I can salvage the third light assembly part to replace and see if that will resolve the problem. However, if it does not resolve it, what other items should be checked?

Thanks.

On my 95 850 with 257k I had the third brake light stop working. I found that the ground was not good. I cleaned up the bottom contacts and that solved my problem. It has been working now for 50k plus miles.
Bob

760 long gone
850 95
s60 07

Cleaned grounds, cleaned connections, put in new bulb, and LIGHTS -- I'm safe to ride behind at eye level again. Thanks!

The housing melts and the terminals between the lower and upper portions of the housings separate. Slide the upper portion of the lamp assy out and inspect the contacts between the 2 halves.