I cannot get the tail lights on my car to work. I have tried to change every bulb, clean all the contacts, RTV all the cracks so water doesn't get in them anymore but still no luck. Some of them definitely work, but there are times when I have my brakes pressed and I cannot signal because the circuit is not complete. I notice the reverse light on the passenger side burns out quick. I have been told to replace the whole unit but I don't want to spend $500 per side and have it fail again. Please help!

 

I feel your pain! I went through issues on my 92 740. A volvo tech said i needed a new tail light because one of the plastic sockets wasnt seated in there right because part of the taillight melted and so it was kinda deformed. Ok -I got a new taillight from ipd and still no good. I checked all the sockets and made sure everything was connected. Finally, I just used a piece of wire and jumped it from the middle tail light,which DID actually work. If you have a middle taillight I suggest doing that. But first: Check your fuses! Also, every bulb has to work or else it could throw off the whole works. The other thing that happened to me once was that I needed the brake bulb light failure relay. In the 740 its an orange round relay located above the ashtray with the other relays. Not hard to replace. So I hope one of these things work for you.

 

Hm, yeah, they did, and they do work just fine most of the time, although they are not the greatest but, hey, they were designed in the '70s and time and the elements take their toll. Hard to say what's going on with yours exactly but I know it can be frustrating sometimes and maddening since it's not a rocket science. They do suffer that socket "warpage" from overheating and mild cases of it can be cured with a Dremmel but sometimes they are too far gone. The aftermarket lights are more apt to warp...

 

Over the course of the last 26 years with our 89 I had replaced the tail light assemblies once. On the other hand I have replaced the printed circuit on each light maybe 3 times. I had also drilled a drain hole in the bottom of the assemblies so water drains if and when the seals dry out and fail. There was also a post I saw years ago where someone hard wired each of the sockets to eliminate the problem with the printed circuit. I find the key is to clean the PC with electrical contact cleaner and use elect. grease when reinstalling the sockets.Mine are usually trouble free and the Sense relay has never been replaced.

 

I have replaced the Brake light relay the week I got this car. As I stated above, I have changed every light bulb at least twice since I got the car. I do not want to give up on this tail light project. I have considered switching to newer tail lights. The design of these tail lights are so poor. Does anyone know when they were updated and if it is possible to swap the tail lights from a newer 740 or 940?

 

On the sedans the lights were pretty much the same till 1989, on the wagons till 1998.

 

[QUOTE=tinkerbelle;421646]Finally, I just used a piece of wire and jumped it from the middle tail light,which DID actually work. [QUOTE]

From the middle of the tail light you mean from the reverse light? So you just connected the ground contacts?


Did you also have issues with the reverse light not working?

 

Drilling drain holes in the tail lights were a huge help. I live in the Pacific Northwest so get quite a bit of rain. Thanks for all the suggestions everyone!