Anyone ever try this? I'd like to install illumination inside the upper tail light sections of my 1994 (62,000 miles, honest)855 Turbo Wagon. I mean, all they are now are "reflectors". In changing a bulb in the lower section, I found there was a narrow (approximately 3/4") cavity in the upper section of the tail light. I figure Volvo didn't want to go the the expense of illuminating them. Anyway, I'd like to find some led bulbs and fixtures that I could cement inside the upper section and connect them to the lower circuit of the the tail (not brake)lights. At the same time, I'd like to find and mount an LED brake light on the spoiler already installed on the car. Any thoughts would be appreciated. (And yes, I know it's just an "ego thing")

Not a bad idea and one that I might try myself if I owned that car but FYI only, it's likely that adding more lights will cause the bulb failure sensor (relay) to trip the dash light. Before doing anything permanent, try temporarily wiring any extra bulbs to make sure you don't cause another new problem, headache.
As mentioned, the OEM Volvo wagon spoiler has a 3rd LED brake lamp installed so yours must be aftermarket.

Thanks, Frank. In speaking to a local auto electric shop, I was told that the use of low voltage LED's would be very unlikely to cause failure in the bulb sensor relay. As to the Spoiler, it IS a Volvo product. Had it installed when I bought the car way back in '94. I know I can buy a new one with the LED Brake Light. .for another 300 bucks, not including painting, but I'd sorta like to avoid that. .my conscience won't let my ego spend that much money.

they sell wagon spoilers for 850 at the dealer.

part # 9184639 (+"347 98"), eurostyle roof spoiler with lights is the name

forgot the +347 98 part...i think it's for the lights...

sorry...forgot to mention this roof spoiler has an integrated brake light in the middle of it...

I have seen a Hella/Volvo concept with gas tubes running the length of the lights, like the old Lincoln Mark 8 came with. It was cool, but no doubt expensive.

VOlvo didn't light up the upper part in the early 90s because LEDs were too expensive and using bulbs in the area would probably cause melting due to the lack of air space and resulting poor heat transfer.

I think it's possible to do what you want, I would get a second set off ebay to fiddle with. Since LEDs use much less energy, the additional drain "should" not have a negative effect.

As for the spoiler, there are aftermarket CHMSLs out there, try googling for them.

Please post how it turns out, you may have a cottage industry starting up!