1996 Volvo 850 Sedan (Base) Brake Lights Out Topic is solved

[jotoya]

Hello,

I've got an interesting problem. My brake lights will not light up - any of them. It's not the bulbs and what is making me concern is that the BFWS in the dash is not displaying anything.

I have:

• Checked ALL the fuses
  No codes
  Bulbs - all new
  The brake switch is new and engaging properly

Any guidance is appreciated,
Thank you

[abscate]

Get the voltmeter out and look for voltage at the bulb holders.

If they are all out, including the LEDs , it’s wiring

[Vova585]

I disagree with voltmeter test. Always use substituted load (bulb with 2 wires attached)which is equal in amp consumption to the component you are testing. Rationale-you may have a broken wire which will have 1 "hair" intact and it will show you 12.5v, but will not be able to carry current to do needed work. Substituted load and only that.
1. Go to the brake light of your preference. Get yourself substituted load and 2 long wires. You need to verify that you have a good ground first before moving forward. 1 wire to "+" of the battery and to the bulb. 2nd wire touch tye ground side of the bulb wiring harness(usually black or brown, but best to have electric diagram to be 100%). No light- broken test equipment(always check your test equipment prior to test), or defective ground.
2. Wiring diagram. I think 3rd brake light should be powered through separate wiring from regular brake lights. So issue is likely "upstream"
3. Me speculating here- last time I read about similar- it was BFwS issue.

[jotoya]

Many thanks to both.

Vova585, might you know how (if any) resolution was found for the BFWS situation?

[Vova585]

BFWS was replaced. But I would arm myself with test light and wiring diagram before calling that.
Found this on neighbor forum. member described some troubleshooting which might help, plus they included repair manual for download(not sure link is working since pointing to us)
https://volvoforums.com/forum/volvo-850 ... 174/page2/

[jotoya]

Many thanks to everyone. It ended up being a faulty brake switch.