Bulb Failure light illuminated goes out when brake pedal is depressed
 

Greetings all I recently purchased a 92 240 sedan and have been introduced to some Volvo Gremlins early in the game. I never made it home the day I purchased the vehicle. Blew a fuse, car quit, dark, no tools, no light, no clue. Went back in daylight changed fuse kept on motoring. The light bulb failure light illuminates when the headlamps are turned on and will go off when you step on the brake pedal..? Could this be a brake switch adjustment? or relay failure? also the ABS light intermittently comes on when driving, the tires were sprayed with armor all when I bought it, could this gum up the sensors? should I try cleaning first? Thanks to all who respond. JPR

I think it is a tail light bulb. When the brake is not pressed, the normal dim light is in operation, which is blown out. When you step on the brake, the wires switch to the bright brake light which turns off the dim light so the warning light goes out. See if all your tail lights work.

+1...

troubleshooting
 

I removed the bulbs and visually inspected each filament and spring connector prongs for corrosion and connectivity. the brake lights are operational in dim and high mode and are the apropriate bulbs 1157. I also inspected the third brake light and it is the correct bulb as well. 1156
I removed a light bulb to simulate failure and the warning system operated correctly. all bulbs are installed and working in the lighting system. The only time I can get the bulb failure light to illuminate is to turn on the parking lights or headlights and when I step on the brake pedal the light goes out..sometimes it will come on again as I have the pedal depressed..it is definitely tied to the brake pedal actuation and as I cycle the pedal I can hear a relay actuating the light cycles with the relay at first then with the pedal depressed and I let off a bit I can make the relay actuate on and off with the light illuminated. Does the brake switch have an adjustment? is the lisence plate light in this circuit? corrosion on fuse 15 or 16? for the bulb fail sense? I cant even find the brake switch in this schematic?

I've got a similar problem that seems to go off and on in my '93 240 WAGON.

I am working on one theory, however yet to try - the grounding wires going to the tailgate, along with the hot wires, seem to have broken and providing intermittent connection. With you sedan, I wonder if you have a similar situation - there's enough current to power the lights, but not enough current perhaps to trigger the bulb warning sensor to sense correct operation.

brake switch
 

Does anyone know how the brake pedal switch affects the circuit? does anyone know where the bulb fail logic box is located?

Kudos to RSPI he was dead on and I almost dismissed his logic after examining the bulbs initially. I checked the easy one first (right side) verified it had 2 filaments and looked at the bulb number (1157) Then after removing the spare tire in 100 degree heat I pulled the bulb, saw 2 filaments and assumed it was an 1157 (damned if it didnt look exactly like the right bulb!) So off I went chasing fuses relays and switches only to keep hearing RSPI's words in my ear;" its the bulb" So off I go to the parts store just to put the bulb theory to rest and damned if I didnt remove a German Flusser 12v P21/5w bulb from the left side! At that point I knew RSPI was right and I was a fool for not listening. Reassembled all,tested system , all functions normal. thanks again rspi I will listen next time

Having same issue... with my volvo 740.

Can't find any info in the manual or anywhere the 3 bulbs on each side per taillight the top one is turn signal, middle one is brake light, and the bottom one is tail light bulb correct?

So the two tail light bulbs have to match up correct or what...