1991 240 Wagon Tail light fuse blowing all the time
 

How's it goin guys? I am friggin stumped here. A quick intro, the car regularly blows the fuse responsible for the tail lights, license plate lights, pretty much everything in the back. I have searched the archived threads for this problem but didn't see much on the fuse blowing, more of a bunch of "they don't work at all" threads.
Since the wires at both hinges were all severed, myself and the owner of the car's dad changed both harnesses that run through there with all new wiring from the volvo dealer...we took the hatch door off and ran all new wire through so now all grounds in that area and inside the hatch door are fixed but this damn fuse still blows figuratively and literally. No one thing is blowing it that I know of either. We tried all functions, brake, reverse lights, turn signals, wiper, hatch lock actuator, defroster, rear dome light, tail lights, everything works and didn't blow the fuse until just a little while after he was pulling out of the garage and it blew. I've just now read up on this infamous red bulb indicator relay deal so I haven't checked into that yet.

I am stumped, I've done tons of electrical work on cars and rewired a damn mustang 5.0 after the org. owner hacked the wiring so I know my way around car wiring and a multimeter but this thing is just so screwy. Any help would be GREAT!


***Also, the car's left tail light assembly is all brand new and on both sides, the top brake/tail light does not work and I still can't figure out why.***

RE: 1991 240 Wagon Tail light fuse blowing all the time
 

It sounds like a short circuit somewhere. From your post, it sounds like the fuse blowing only occurs when the engine is running? I would check the wiring diagram and see how many wires the tail light wires cross, especially when the engine runs. It's got to be feeding more current than the fuse can handle, so it's shorting across a hot wire somewhere. My guess it's a hot wire from some aspect of the ignition system.

Good luck!

RE: 1991 240 Wagon Tail light fuse blowing all the time
 

The top brake/tail lights could be a fog lights. They are on my '86, both sides. Rocker switch above the headlight switch controls the fog lights.

Note: in some jurisdictions, for some Volvos, the fog lights may be on one side only, or non-existent. Also some guys like to hook the rear fog lights up in parallel with the brake lights for better visibility.

RE: 1991 240 Wagon Tail light fuse blowing all the time
 

I had a 240 that the courtesy light/seat belt warning lite in the back seat would blow the running lite fuse when the ignition was on. It was grounding under the carpet in the tunnel between the front seats by the ebrake.