Lights out/bulbs and fuses fine
 

I had an apparent short-circuit situation when I was changing a bulb in my passenger side headlight. Shortly after, I noticed a flickering of several lights in the car. I also heard my door locks activate along with the fuel door. After, I noticed my driver side brake light, backup light and taillight; passenger side rear blinker and front passenger side auxiliary light (inside the headlight housing) all stopped working. My interior lights all work independently (when buttons are pushed), but don't activate when any door is opened. Additionally, the top mounted brake light only comes on for a half a second when the pedal is pressed, then goes out.

I tried and tested all the bulbs in both taillight housings, even buying and replacing all new in the rear to be sure. I also checked all the fuses for all these bulbs which all turned out to be fine.

Eventually, the blinker started working again on its own. When I replaced the backup lamp it lit for a few seconds but caused the fuse to blow. When I replaced the fuse it now works fine. All other bulbs mentioned still don't operate.

In my experience, it's always been either a bulb or a fuse when a light goes out. In this case I can't figure out what to do. Any input on how to get these remaining lights going again would be greatly appreciated.

Thanks in advance.

Check all the fuses, not just the ones for lights. I once fixed a strange interior light issue when I found an unrelated blown fuse.

If all the fuses are good then the most likely culprit is the CEM.

Thanks for the feedback. I have tried all the other fuses and they're fine. Is the CEM something that can be repaired, or would I have to buy a new one? Do you know where mine would be located?

Thanks again.

I've heard of it being repaired. I've never done it though. One person on here replaced one of the electronic parts that make a ground for the low beams. (Something called a MOSFET or some such name) I'm not an electrical engineer, wish I could help more. Try searching for low beams not working.

Thanks again for all your help. I found a company that swaps out the info from your CEM to a new used unit. A little over 400 shipped next day (3 days down time total). Do you know if the car is driveable at all while the CEM is out?

I doubt it but that is strictly a guess.

Thanks again, Hudini. I guess it's a rent a car for a few days then. ;D

After a little further investigation, it turns out the job is going to cost me a lot more than I thought. To replace the CEM I'd have to purchase a new CEM ($550) and send the new and used ones in to the company so they can transfer the vehicle's info ($249), plus shipping ($160). I'd have to get a rental car in the meantime, while waiting for it to come back ($100+?). And then have the car taken to a Volvo dealer after I install the new CEM to have the computer flashed to get it working ($150). Not worth it to me.

I just decided to wire the left and right brake/tail lights together, so that both come on at the same time now. They look exactly as they did before. Both back up lights are working by themselves, and all blinker lights work also, so this solution works fine for me. The only thing is that the interior lights as I mentioned, still don't come on with the door opening (although they all work when manually turned on via the interior switches), but that's no problem. $200 or $300 would have made sense for me, but spending $1100, $1200 or more just because of a couple of lights does not.

Again, Hudini, thanks for all your suggestions and help.