Hello everybody,
My name is Ryan and I'm a new member to this wonderful forum! I own a 1992 240 with 190k miles and automatic trans. I bought it off a third owner and what do I know, the brake light problem persists after changing bulbs and all. I had enough of it so I decided to remove the knee cover below the steering wheel to be able to find the bulb failure relay. I was surprised to see that one of wires going to the relay have been cut. I posted a pic so you have an idea. That wire goes to the "K" part of relay. I wonder what is the purpose of that wire and what should I do about it?
Thanks!
Ryan

 

none of those crimp-on splices are original, either. eek.

the blue-yellow wire is the wire to the bulb-out failure light. cutting it effectively disables the bulb out sensor.

pin 1 - blue-yellow - bulb failure warning light
pin 2 - blue - low beam left
pin 3 NC
pin 4 NC
pin 5 - brown-black, to 3rd brake light
pin 6 - grey, from step relay (low beams)
pin 7 - blue - right low beam
pin 8 - ground for warning light
pin 9 - blue-red - brake light switch
pin 10 - yellow-grey, brake light left
pin 11 - yellow - brake light right
pin 12 - brown-white - tail light right
pin 13 - red - tail light left
pin 14 - grey - from fuse 16 (power for right tail)
pin 15 - white - from fuse 15 (power for left tail)

 

your brake light circuit...

battery to fuse panel to fuse 7 to green-red wire to brake switch (at brake pedal).
brake switch to blue-red wire to bulb sensor pin 9

bulb sensor pin 5 to brown-black wire to conenctor 'F' pin 15 to brown-black to high level brake light

bulb sensor pin 10 to yellow-grey to connector 'F' pin 19 to left brake light

bulb sensor pin 11 to yellow to connector 'F' pin 20 to right brake light.


connector 'F' is a 2x12 (24 pin total) connector that I think is somewhere near the back of the fuse panel. has a whole PILE of stuff on it


[note, this is all from Volvo "Greenbook" TP-31953/1, 1992 240 Wiring Diagrams]

 

This is weird to me, because I have the same model year with a cut wire, but... I don't have that huge relay. Just a small normal type with relay missing completely.

 

they ALL have that cylindrical bulb-out-sensor (its not really a relay), with the round connector of about 15 pins, so whatever you're looking at is likely something else.

 

somebody got sick of the bulb light being on so they snipped the wire instead of fixing the core issue. Repair wire, fix core issue, enjoy car! If it's a sedan the tail light circuit board can be flaky and cause your issues.

 

 

empty for a reason. Proabably fog lights or something. Dont trip. We went thru this on this forum with another guy that saw that and freaked out too. Natural instict to go WTF!, but unless you have components that aren't working. Don't be surprised to find a few plugs without a home. I have seen sooo many cars with test plugs, or plugs for options that the car didn't have.


Fix your brake lights so you don't get rear ended.

 

this is great info and just what I need to track down the cause of all 3 brake lights suddenly not working (left, right, high center). Do you know if this is the same wiring for a 1993 940 turbo wagon?

 

Check your fuse first, then power to the switch, then onto the bulb out relay

 

Fuse was fine. I'll check the switch next. Do you mean the switch that's activated by the pressing the pedal? If yes, is it down around the pedal somewhere?

 

`Yes --

 

Am I crazy or is there a vacuum line going into my brake light switch? What is this for and can it effect the brake lights functioning?

coincidentally after changing out the breather box (and undoing vacuum lines in the process) my cruise control quit working. So could a vacuum line issue be causing my brake lights to not work? Seems crazy to me but I swear there is a vacuum line going into my brake light switch.

 

So now that I found the actual brake light switch, what color is the wire with the power running from fuse 4 to the switch? I see one connector with a green and yellow wire. And another connector with 2 brown and yellow wires. Which one is power?

 

Use your test light, or can you match a wire color with the one at the fuse for the brake lights?

 

The vacuum line is going to your cruise control dump valve which deactivates the cruise when you step on the brake pedal, not the brake switch.

 

The vacuum line is going to the dump switch which deactivates the cruise when you step on the brake pedal. It can be the cause of your CC no working if it's not holding vacuum.

 

Thanks for all the advice (and patience as I sort this out one clumsy step at at time). I determined that I have power going into and out of the brake light switch so from what I understand, it's on to the bulb integrity sensor to test that. From what I can tell (and possibly see) it is located in the center console behind the fuse box and two rows of relays on my 1993 940 turbo wagon. How am I supposed to access that part? I can barely see it, let alone lay my hand on it to work on it by going in through the hole where the ashtray was. Do I need to remove the radio to access it? Or could I remove the side panel on the center console? If so, how?

Or could I be looking at the wrong part again? I am 95% sure it's not under the dash on the drivers side like on the 240s I read about in other posts. Any help determining the location of the bulb integrity sensor and how to access it well enough to check for current running into and out of it would be greatly appreciated.

Thanks

 

Bulb failure "relay" is a 1362370. Red, round and located under the drivers side of the dash - probably have to remove the knee bolster to easily get to it.

 

Sorry for the delay. I thought I replied to this last week.

I located the bulb failure relay under the radio behind the fuse box and behind a row of relays. I have a '93 940T wagon so perhaps they moved the location of this part at some point. I found a replacement part at a junkyard from a '94 940T sedan. it was in the same location behind the fuse box.

Everything works great now. Thanks again for all the advice.

Jeff