Tonight I found that my brake lights in the 245 were not working.

The bulb failure sensor didn't trigger the orange light on the dash when depressing the pedal, so the only way I would have found out my brake lights weren't working would be to get rearended eventually.

And since my girlfriend is taking it on a 300 mile trip, I figured I had better solve the problem.

So I pulled the wires at the brake pedal switch and checked for continuity.

The switch worked.

Next, I went and rattled the bulbs in their holders and checked the wiring.. Everything was a-ok..

The fuses left something to be desired, but all work.

(note to self to replace with glass tube style)

Anyway, after contemplating where my problem could lie, I pulled the bulb failure sensor.

Then I completed the circuit to the brake pedal switch and the wire from it to the sensor with one of the tail light wires.

Wah-lah.. the brake light came on.

It turns out the fault was in the bulb failure sensor.

What to do???

the contacts were all good, and I opened it up.. nothing appeared fried in the circuitry..

So I soldered a bridge between all 4 of the wires that controlled the rear braking.

(main wire from the brake pedal, the two (right and left) tail lamp wires and the 3rd brake light wire)

Well, success is mine.. The brake lights now work, but at a price...

every time you push the pedal, the failure light on the dash comes on.

OH well will do for now.

Anyway, My whole question is do these things fail that often?>

And what might have caused mine to fail?

Also, are they cheap to replace?

I'd like everything to work 'correctly'

but was happy I could get by for now.

Luke

I had the exact same problem a couple of months ago. According to Board members and the volvo dealer, the bulb failure sensor goes out at about 100,000 miles or so. At my Volvo dealer they charge $115 dollars for a new one and $43 bucks extra to install it.

Very costly for something that looks like the top of an aerosol can.

man..

well, my car has 200,000 miles on it.

And I will install ANYONE's sensor for 21.00 (less than half the dealer cost:)

My solder bridge is working and I have some really bright brake lights now :)

I had the same problem about a year ago. I opened up the bulb failure sensor and resoldered every contact. Must have been a cold solder joint or crack somewhere. Everything's been working fine since.

Try removing the solder bridges. You might find that heating up those joints solved the problem.

I have the same symptom as Luke does. Mine is an '86 244DL sedan.

Where is the bulb-failure sensor located?

On my '87 240DL it's located just under the dash to the left of the steering column. It's held on with a metal clip (kinda like the overdrive relay). Mine's red and is manufactured by Hella. It's a tapered cylinder about 3" long, and the plug end almost looks like a radio tube. It's kinda tough to take apart, but I had success using a jeweler's screwdriver. I suppose any tiny flat blade screw driver will do. Once you've got it opened, reheat every solder joint. Some of the joints are pretty beefy, so it's nice to have a high wattage (> 30) gun.

Luke -

I have never had a failure, although my 1986 244 has a suspicious symptom. (failure light when brake lights on, and I've run all the simple tests) A non-mechanic friend had to put in a new one, not cheap. The p/n for hi-level brake light models is not same as older models. I would try one from a boneyard first, little labor and small chance of botching the job. Just make sure the number match. Post with your results.

Good Luck,

Bob