940, 1994
All of my rear brake lights suddenly don't work. An problem indicator light pops up at the dashboard, but the Volvo manual doesn't show what it means. Took it to a local non-Volvo automotive shop and they said that the "sensors" had to be replaced (ie.$250) Fuses appeared intact. Should I believe him? Didn't know there was such as thing as sensors involved in the brake light system, except ABS sensors. Anybody have some ideas on what the problem might be. Maybe a less expensive fix?

Thanks.
cpapakirk

If you want to send me your email address I have a trouble shooting 'thing' I wrote up from my 200 when I had the same problem. I'm betting it is The Bulb Failure Sensor. Ironic...when the sensor goes bad you end up with zero brake lights.
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'75 Jeep CJ5 345Hp ChevyPwr and two motorcycles: it wasn't Volvos safety , it was Longevity that sold me

Since it's unlikely that the bulbs allfailed at once, I would first check the fuse, and then go after the bulb-out relay. Thats' the thing that turns on the bulb warning light. It's a big red can on the front left of the fusebox.
Installation should require nothing more than removal of the coin tray/cig lighter above it, which requires just a phillips or torx screwdriver.
The best source is a used one- the dealer gets far too much for it. This is probably the "sensor" they're referring to, though that's not really the complete description.
I bet you can get one for $10 at a junkyard from any old 740/760/940.
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Rob Bareiss, New London CT ::: '86 244DL- 215K, 87 244DL- 230K, 88 744GLE- 198K, 91 244 180K

There are no sensors involved no, but a switch and a relay. The switch is located above the brake light pedal. If you have cruise, there are two switches up there and the brake light one will be the one higher up and with a wire going to the cruise switch and one going up into the dash. If you don't have cruise, there is only one. A bit of a pain to remove but not too bad, a new one is cheap. The relay is the huge green round one located on the main relay board. This is the bulb failure relay which controls the light you see, i.e. the bulb failure indicator light. This relay is connected to the circuits of all the main bulbs and senses changes in drawn current. It is of course possible that it is broken on the brake light circuit and thus preventing that from completing when you press the brake pedal. However, if all the brake lights are out and replacing the bulbs does not help, then replace the switch or at least check it, only then go to the relay.
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George Holmer, Belgium, Europe, 1987 745 GLE Turbo Diesel Intercooler (D24TIC/ZF22) 200k; 1988 745 Turbo Intercooler (B230ET/M46) 290k; 1988 745 GL (B200E/M47) 190k

If all three brake lights quit at the same time, AND the switch and fuses are fine then I would bet it is the bulbout relay. In the 200 and 700 series cars (and probably yours as well) it is a big red round relay. It is the only one like it so you won't be confused. New ones are very pricey, but most often if you open it up and examine the solder joints (and it has a number of them) you will find one that is bad. If you locate the bad joint and resolder it you can fix your problem for nothing. If you need some incentive just call your dealer and price a new one. You can also purchase used ones from a recycler.

Randy

Thanks to all bricksters for your answers. I will check on the bulb relay, which sounds like the source of the problem. Volvo dealer charges $129 for a new one, not including labor, etc.

cpapakirk
940, '94

Now that's a new one on me. I didn't know the bulb-failure relay going bad could cause all lights to go out.

Very interesting.
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Mike F - 1984 244 DL - 220,000 miles - with Euro headlights and lots of gauges