Even after checking instructions in and I am badly melting the back of the parking/brake light lenses with the CP 32-3 (21/5W) bulb holder sockets, left and right on the '86 760T. With the lights on, only the 5W filaments of the 21/5W bulbs left and right appear to be on because when I turn on the rear fog lights (21W) these appear much brighter. When I press the brake pedal, then brake and fog lights appear equally bright. The tail lights are brand new aftermarket from Frank's Auto Parts, made in Italy, they tell me, by the supplier to Scan Tech. Anyhow, not a good buy because they came only with gaskets (not circuit boards or bulb holders) and I later found FCPGroton has the Scan-Tech tail lights with gaskets, circuit boards and bulb holders for less than I paid. If you are around Steve, you may want to edit id=339186 and id=340033 for 700/900 FAQ. Please, can someone help?

I had a similar experience with our '89 744 Ti.

I did not realize that there were left and right sockets for the tail light bulbs and had swapped them during troubleshooting.

I found out about the left and right issue when I removed and completely disassembled one of the tail lights.

The heat had started to melt the lenses and the slots that the sockets insert into.

If you have the sockets on the correct sides, perhaps you have the circuit boards mixed up, if that is possible.

Bad grounds can cause a lot of problems, but in my experience the bulbs burn less bright due to resistance, releasing less heat.

I think that you are looking for a short.
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3 8s & 2 7s 740,000 miles total

Hello James and thank you for your reply. Searching the topic here at Brickboard I came across the bulb holder issue at (white on the passenger side, black on the driver side), but that is the way the bulb holders have been in the car all along. Still, I seem to remember that may years ago I damaged one bulb holder (white, I think) and was sold another one from Volvo but black at a local European auto parts store. I doubt it is possible to mix up the circit boards (films) because of the way they are made and folded where the wire harness connects. Today, I cleaned those circuit boards first with a soft emery board used for buffing fingernails, and then with CRC electronic contact cleaner spray, before I coated contact surfaces with dialectic grease to keep them clean. Then, I put in a pair of brand new 12V Osram P21/5W bulbs with the BAY15d base. This is the OEM type of bulb specified in the owner's manual, but is it any different from 1157 bulbs? I checked that only the 5W filaments are on with parking lights on and the 21W filaments come on only when the brake spedal is depressed, both right and left sides. The lights have worked well all day today, but those lenses are likely melting again, even after I heated them and shaped them back as best I could today. Please, give me your suggestions to trace that short, as it is the only avenue I have left now. The other possibility that comes to mind is bad quality of the tail lights I bought from Frank's Auto Parts (New and Used Volvo Parts), but they refused to help. Best regards.

Weird. How are the grounds?

I was thinking about checking the grounds after searching the problem and reading a couple of hundred posts. Any sugggestions on how best to check grounds? The bulbs on each side, left and right, become incredibly hot as soon as you apply the brakes, hot enough so they have distorted the back of the lenses on both left and right and made the plastic surface bubble up. BTW, I read you broke a leg, are you getting along?

Leg is doing great, but not far enough along to allow me to replace the cooling system on my '95 yet. Later in July...

The grounds are in the wells right next to the rear lamp circuit boards: easy to see with a flashlight. I would clean them off, apply some OxGard conductive grease, and see what happens. While the bulbs do get hot, they should not be hot enough to distort the plastic unless the plastic is made of old milkjugs or something similar. I would send them back to the vendor: sounds like poor quality control.

Glad to hear the leg is doing great. Not long ago, Nick recommended to me the Nissens aluminum and plastic radiator over the Volvo one, at $100 less. From your post, the Nissens looked good to you too, so you should be OK when you get around to put it in the car. Let us know how it goes. BTW, recently you wrote a great post explaining possible galvanic corrosion of engine aluminum with a brass radiator. I did telephone Frank's Auto Parts about the tail lights, but they said no warranty at all. Both on the left and right tail light, the lens that holds the 21/5W brake/parking light bulb melted and collapsed like a piece of chocolate in the sun. Funny thing is the lights worked well until those things melted. That is, the 5W filament burns with parking and driving lights on, and the 21W filament comes on only with the brakes. Moreover, I do not even drive in bumper to bumper traffic the would keep the brake lights on. It sure looks like the quality is not so good on those tail lights, like you say. Perhaps I should post for those that may need tail lights that Swedish Engineering has the Volvo ones on sale and FCPGroton has Scan-Tech units (complete with gasket, circuit board and bulb sockets) cheap. Best regards.