My '97 960 has had a complete braking light failure. Have T/S as much as I possibly can w/o schematics and have yet to find anything. All wires in the trunk ohm out perfectly. Have power to the fuse and the fuse is good with power to the other side of the fuse. Brake switch ohms out good when pressed however there is no poer to either one of the wires to the switch. Please help if you can. I am an aircraft electrician and know how to shoot wires but I can't go much farther w/o a schematic b/c I don't particularly feel like tearing into the main bundles. So if anyone has seen this problem before and has any ideas or if someone could provide me with some schematics I would be eternaly gratefull. Thanx - K_LAB

You have no power at all to the brakelight switch?Does your car have 2 switches?Some had 2 one for the cruise control and the other for the brake lights.

I am having the same exact problem in my 1997 960, schematics would be great. Folks have talked about similar issues with the 940, they refer to the bulb failure circuit or relay that may have cracked or cold solder joints near the high current lugs. Howver, I cannot locate this bulb failure system in my car. Any ideas on it's location?

First, call IPD at 800-444-6473, and talk to them about the problem. For a 940 the "Bulb Integrity Sensor" is $72.00. I know because I ordered one today. Second, to find this Sensor and other sensor or relays open the panel to the fuse panel, deeper inside is the sensor. On the 940 it is red. From the IPD catalog..

First check:

1. Fuse
2. Brake Switch
3. Tailight circuit boards, expecially at the connector
4. Bulb and socket condition

Hope this helps.........

Wedwagon

Had a similar problem just a few months ago on my 94 940. The problem turned out to be the light sensor "relay", a module that senses when your light bulbs have burned out and then lights a light on your dash board. You can replace this unit which is a red "relay" type unit behind the fuse block (at least on my 940), or if you can live without having a lost bulb indication, get a schematic (I got mine reasonably priced at eautorepair.net) and jumper the input of the relay to the output and you will be in business. That is what I did after getting an inspection ticket and it solved the problem. I can give more details if you think that the 940 and 960 have the same circuit. Hope this helps.

I have had a similar problem with my 95 940. My bulb failure light has been intermittently flashing. Wasn't sure that there was an actual problem since my brake lights seemed to be working okay when I checked them. However, this morning when I got it inspected, it failed for a suspected problem with the brake light switch. The people at the inspection station suggested that I take it to someone who works on Volvos specifically to have it fixed. I don't really know much about fixing my own car, but if someone could guide me on what I need to do to fix it, I'd be more than willing to try. I'm in vet school right now and need to save all the money I can.

I got this update reply from JoeV:-


Update - It turned out to be the brake light switch, it was
sticking, gave it shot of WD and it is working ok now. I would have
replaced it, but it was up under the dash, above another switch
that is on the brake assembly that i am assuming to be a cruise
control switch. Yes, there are two switches. Hope this helps
someone else. Thanks to all who offered their thoughts. I am
now off to fix my flashing transmission indicator light. Regards
to all.
============

Thanks for the update, JoeV!

Hello I also have the same brake light problem with my 1994 940 Trubo, ALL the brake lights don't work, and it not the fuse, not the brake light switch which when activated has +12 vots on the switch output, but no power to any light in the tail. I have seen post about the "Bulb Out Sensor relay" causing the problem and also about 2nd brake switch (for cruise control) but can some that has a wiring diagram tell me if the 2nd brake switch is used in the circuit for brake light or only for the cruise circuit. Or can someone tell me that they had no brake light at all and after replacing the "Bulb Out Sensor Relay" that it fixed the problem.

Thanks Alot All!

You could try http://www.wirediagram.com/ it will cost you $4 but if it helps solve the problem it would be worth it

OK Since no reply to my post, I took a chance and changed the "Bulb Out Sensor Relay" and that fixed the problem, luckly I had the same exact relay in my 1990 740.

Regards

Wiring diagrams--http://www.volvo-off.pl/old/volvo940/download/VOLVO_940_1993.pdf