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Both brake lights on my 1994 940 are out, and new bulbs don't help. Not getting voltage to the light fixture. Fuse #4, for the brake lights, is intact.
Before I go to what seems like a lot of trouble to find, remove, and test the brake pedal switch (I read that the easiest way to get to it is by removing the instrument cluster and reaching down to it), is there anything else I should look at?
--
1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx
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Thank you to you all. It was the bulb failure relay. I swapped it out for the known good one in Thunderbolt/Brunhilde, and voila, brake lights again.
FWIW, Tasca wants about $124 for the part, FCP has a KAE equivalent for $58.
I'm going to break out the soldering gear and go over the "bad" relay and see if I can fix it.
There will be a post about poor Thunderbolt/Brunhilde in a bit.
Again, many thanks to you all.
--
1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco
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hi N7- had this exact problem a few mos. ago. suspected brake switch since both lights appeared stinko and fuse was good. car is 92 245. failure of that switch is rare. no volts to switch terminals. replaced the bulb failure relay. problem solved . bought from autozone, $60. had to remove panel from below wheel to access relay. did cuss though. regards oldduke
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I'm surprised more people didn't pipe on. The BFR is a very common failure point when the Brakes do not light AND you do not get a warning on the cluster that bulbs are out. You need to pull the red case away from the black tabs. Pull up on the Black to get the guts out. The issue is usually at the tall pins that connect one circuit board from the other.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html http://cleanflametrap.com/tony/
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It is most likely to be the Lamp Failure Relay. They can be repaired, and there is information in the FAQ.
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john
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I think its easier to approach the brake light switch from below. I just replaced my switch as preventive maintenance last January. Remove the driver-side above knee plastic cover under the dashboard. You could see the switch just by looking upwards following the brake pedal. Some 940 models have above knee bolster bar that might hinder your view a bit. Mine doesn't.
The wiring scheme is that the brake switch lets power in from the battery to the brake circuit. So if you could jump/short the two wires of the brake switch the brake lamps should light up (and you'll know the switch is defective).
If you need to replace the brake switch, use a twelve sided 17mm ring spanner as the narrow space there limits the use of any other tool. Just undo the fastening nut a bit then you could spin the switch out after disconnecting its wire connectors.
Tip: If you live in tropical climate open all car doors or put a table fan facing the work. Lots of sweating expected working within that small space...
Regards,
Amarin.
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"...17mm ring spanner..."
I like that name. Much more interesting than what I was taught - "box end" or "closed end" wrench.
--
Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (getting ever closer to road worthiness)
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How's the third brake light? If that's inop too, most likely it's the red round double decker relay for the failed bulb notification.
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Dear tedv,
Hope you're well. I think you're on target. Before trying to find a broken wire, I'd swap-out the red-orange, cylindrical bulb failure relay with a "known good" or new replacement. If that doesn't restore brake light function and cruise control, then I'd go further.
Even so, I'd check for corrosion on grounds at the rear of the car. Deoxit or a similar corrosion-remover could put things in good order.
Hope this helps.
Yours faithfully,
Spook
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Does your car have cruise control?
If so, does it cancel when you tap the brake pedal?
Can someone confirm that the C/C cancel and brake lights feed from the same pedal switch?
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The car does have cruise control, but it doesn't work.
The switch for the cruise control is different from the one for the brake lights, I think. I base that opinion on the two different switches that are available for the car. The one for the cruise control has a port for a vacuum to attach to, as well as the little electrical connector. The one for the brake lights has only the two electrical connections and looks completely different.
Further, I think the post that I found, and can't find again, about getting to the brake light switch through the instrument cluster opening, also mentioned that the brake switch and cruise control switch are different switches.
I have the electrical diagrams, somewhere, on old backups of old hard drives, but it would take forever to find them. . .
PS: It is nice to see someone I recognize from the "old-days" when I was on this forum after I got my first 740 16 years ago.
--
1955 Human, Scott; 1991 745 Turbo, Thunderbolt; 1994 940, Straxx; 2008 C70, Draco
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"...It is nice to see someone I recognize from the "old-days"..."
And likewise. Unfortunately, in my case, older but no wiser.
I looked at a wiring diagram online;
The brake light switch has a Grn/Yel coming from fuse #4,and a Yel/Brn running to the bulb malfunction sensor.
http://www.volvowiringdiagrams.com/?dir=volvo/940%20Wiring%20Diagrams
Have you checked the fuse?
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