I recently bought a 77 242dl. My dad recently passed and was a sentimental purchase. No experience working on Volvos and am more or less a oil/filter tires and car stereo level mechanic (meaning i'm not a mechanic at all).

One of the brake lights wasn't working when I bought it. Figured it was just a bulb. Replaced it. No luck.

It's hard working on brake lights since you can't see what's going on back there. Ran a wire from taillight to brake light to check bulb and socket. It lights up. So figure the problem must be the driver side wiring for the brake light. I stupidly figured I'd just run a wire from the working passenger brake light to the driver side. That burned out the socket on the passenger side.

Long story short, I have no brake lights including a burned out passenger side brake socket and doesn't seem my reverse lights work either (not sure they ever worked or not).

Any ideas on how to approach this? Having trouble even finding the sockets and looks like maybe the whole 4 socket assembly has to be replaced as one piece?

I just spent too much money on a sentimental car and now I can't even drive it around.

Any help on where to start would be insanely appreciated! Thanks for having me on Volvo Forums and being patient with my amateurism.

 

I should also correct that the passenger side reverse light did work. It was only when I tried splitting the working power cord to both the driver and passenger that it seemed to stop working altogether.

 

finding replacement 77 tail light assemblies is going to be hard, I see *VERY* few of those early versions on the road anymore... at least a few years ago you could still get the ones for the later 80s/early 90s style.

the first thing I would have done would have been to check for voltage on the wire to the non-functioning brake light.

 

OK what year is this car?
A pre 1979 should have a flat tail lamp assembly, the lens comes off from the outside of the car to replace the bulbs.

A 1979 and up tail lamp the bulb holders are are the inside and commonly melt - On the 79-93 tail lamps It is very easy to move the brake light bulb position to a non melted place - What tail lamps do you have? Same thing with the reverse lamps, easy to fix if 1979 and up.

 

It’s a ‘77. I believe the tailight assembly is original (maybe with newer lenses). Yes the bulbs are replaced by removing the Lenses from the outside.

 

So I found the passenger reverse and drivers side brake light wires don't have power. Fuses are all ok. Is there a controller somewhere that all the taillight stuff goes through?

 

purdy simple circuit.... lets see.

power comes from the 'positive terminal' (which at least on later 240's is on the left fender near the strut tower, and is a small flat plastic box with a whole pile of red wires coming out, this is the main source of 12V for nearly everything)
positive terminal to fuses 6/7/8
fuse 8 to brake switch (at the brake pedal) on a 1mm Green wire
brake switch, blue-red wire goes to 'bulb failure warning relay' pin 1
bulb failure warning relay pin 2, yellow wire to right brake light
bulb failure warning relay pin 3, yellow wire to left brake light

oh, the two yellow wires go through an 8 pin (2x4) connector near the fuse panel, one yellow wire is on pin 1, the other on pin 6

the bulb out relay is a quite simple device, shaped like a frozen OJ can, it has a set of counter-wound coils around a magnetic reed relay. as long as the current from pin 1 to 2 is the same as pin 1 to 3, the reed stays open, if there's significant difference in this current, the reed closes and lights the 'bulb failure' indicator on the dashboard. other lamp circuits that go through this relay include the low (but not high) headlamps, the /rear/ parking lamps (but not the front). the bulb out relay is tucked up under the dash, near the steering column, it has around 12 pins arranged in a circle. if its failed, some people have been known to take it apart and gut it, and replace everything with jumper wires like...

pins 1-2-3 (brake lights)
pins 4-5-6 (use decent gauge wire, these are the headlight low beams)
pins 7-9 (left tail lights and license plate lights)
pins 8-10 (right tail lights and license plate lights)
leave pins 11 and 12 disconnected.

note all this is specific to the 1977, there were some changes in '78, like the brake lifhts are on fuse 6 instead of 8

 

The brake lights, the rear parking lights and the low beam headlamps get their power through the bulb out relay - (but not the reverse lamps)

brake light power comes from the fuse to the switch to the bulb out relay, then to the rear of the car

 

oh, all the wiring for the tail lights goes from near the fuse panel down to the floor, then along the left door sills, over the rear wheel hump and to the left tail light, with wires branching to the right tail light assembly.

 

Thank you Pierce and Hoonk. This is extremely helpful!

 

Also, check that you have a a dual filament bulb with the three prong socket in the correct spot for the brake light…

Mine all act up when the spare tire rolls back or it shifts little bit I just jiggle the connection a bit and it works again. Although the same can be said for the entire car…