92 740T brake lights hate me

Guest · Post by **Guest** » 23 Apr 2003, 18:55

Must kill Volvo.

Resoldered and retested. No dice. Checked power at fuse and switch: good. I can only test one side of the fuse terminal at a time though, because they're blade fuses and bury themselves in the panel to a depth which prohibits probing with the 12V light. I replaced both bulbs and the fuse to make sure. All good. Grounds are good.

The wiring diagram in Chilton's indicates that there's nothing between the bulb sensor and the stop lights. I'm at a loss now; I guess I'll try to find someone who has a similar model with the same relay and beg them to let me swap it out instead of diagnosis by purchase.

Any other suggestions?

Volvord · Post by **Volvord** » 23 Apr 2003, 19:23

Don't kill your car, the Chilton's wiring diagrams are very bad. Send your e-mail address to me at [email protected] I will send you a complete detailed wiring diagram for your car

Guest · Post by **Guest** » 26 Apr 2003, 23:32

ME BOSS! BRAKE LIGHTS NOT!

Took the low-tech road, and convinced another brickster to let me swap out his bulb failure sensor for mine. BINGO.

The sensor I ordered was faulty also, and my resolder job must have sucked, although I was quite careful and re-flowed everything per the Heathkit instructions on brickboard.

Also cleaned throttle body and intake hoses, etc. today. Tomorrow, tranny fluid change and turbo drain line mod ala stu spencer.

I should clearly be hired by Volvo post-haste to correct any nasty engineering problems they may be having, as I am obviously a genius.

Volvord · Post by **Volvord** » 27 Apr 2003, 09:06

Congratulation on a job well done

There is such satisfaction in accomplishing a difficult task, who knows what your future may bring

jake1 · Post by **jake1** » 02 May 2003, 15:42

Where is the bulb sensor? I have tried to fix the light from coming on when turning on headlights. The lights all work fine but that light in the dash drives me crazy!
thanks

Volvord · Post by **Volvord** » 02 May 2003, 18:28

The bulb sensor is with the relays behind the fuse panel, but I think you will find the reason your bulb failure light comes on is because you have mismatched bulbs in your lights. The Volvo system is very sensitive and installing slightly different wattage of bulbs will cause the system to trigger. Did you recently replace a park, tail light or headlight bulb? Chances are it is not exactly the same as the bulb on the other side, replace the other bulb with the the same one you replaced and I am sure your problem will be fixed.

Guest · Post by **Guest** » 03 May 2003, 11:41

I completely agree, and highly recommend that you listen to anything Volvord has to say about such things. I just had this conversation with someone the other day at the counter of a supply store. She had asked about Volvo bulbs for her ehadlights, and came back with one of them. I told her that she should replace both of them (same brand, everything) or the bulb failure sensor comes on.

One handy tip: if you have to remove the sensor for some reason, sit in the passenger seat when doing so. It's a little easier to maneuver around, as there's some clearance (not much) on the left side of the relay panel. The bulb sensor is all the way in back on the left, and looks like a coke can.

Guest · Post by **Guest** » 03 May 2003, 11:50

BTW, I have brake lights now. I ordered that replacement part from a used shop in Jersey. When the sensor they sent me didn't work, I figured I'd have to buy another. Out of curiosity, I called the shop that sent me the sensors in the first place (a mustang/ford/volvo shop), and told him the part didn't work. I didn't think he'd do anything other than say "Hey-you bought a used part cheap".

I was wrong. He sent me TWO more sensors (by UPS-I received them two days later), just to make sure. Very reputable guy (Brian's used volvo parts-found him on ebay).

Some people are really, really cool. And now my brake lights work!