1997 850 Brake Light Issue

mash · Post by **mash** » 22 Apr 2015, 10:35

Hey,

I'm having some trouble with the brake light that's located on the rear window (Sedan). It doesn't work and every time I brake, the bulb failure warning light on the dashboard illuminates. I replaced the bulb and it seemed to work then it stopped working again after I replaced another bulb that wasn't working in the tail light. Has anyone else had this issue and what can I do to check for the reason?

Thanks

crlande · Post by **crlande** » 22 Apr 2015, 13:07

Having same issue. Bad contacts somewhere. At times it works, sometimes a good bump fixes it for awhile.

Post by **Ozark Lee** » 22 Apr 2015, 15:52

The contacts at the base of the assembly get loose, they lose their springiness, and you can often get them to work again by bending the contacts on the bottom of the base down.

...Lee

mash · Post by **mash** » 22 Apr 2015, 21:45

Thanks for the response Lee. I'll give that a try and see if it works!

Cheers

mash · Post by **mash** » 28 Apr 2015, 15:17

Tried that and it didn't seem to work. Does anyone know I can get in and check the wiring by the trunk doors? Maybe something is loose. They came on for one trip yesterday and now it's back to not working so at least I know the bulb is good!

Post by **abscate** » 30 Apr 2015, 07:48

Do a search for tailgate wiring problem - there are a couple of great threads here on how the wiring breaks over the left rear hinge, and how to fix. This is very likely your problem

here is one such thread

https://www.matthewsvolvosite.com/forums ... em#p331961

Post by **jgc470** » 09 May 2015, 16:23

I am curious, if you found the source of your problem. I had a similar issue, and while exploring the problem, I found the ANALOGUE device which feedback open circuits to the system. As I recall, it is at the rear of the drivers side taillights. The device can be circumvented (It is a German piece of technology, which is not available). Somewhere in MVS world, there is an explanation of it, and how to alter it. All the rear light system on my 1996 lead to it.

Post by **Ozark Lee** » 10 May 2015, 00:15

jgc470 wrote:I am curious, if you found the source of your problem. I had a similar issue, and while exploring the problem, I found the ANALOGUE device which feedback open circuits to the system. As I recall, it is at the rear of the drivers side taillights. The device can be circumvented (It is a German piece of technology, which is not available). Somewhere in MVS world, there is an explanation of it, and how to alter it. All the rear light system on my 1996 lead to it.

That is the lamp monitor circuit that gives the lamp malfunction indication on the instrument cluster.

...Lee

mash · Post by **mash** » 10 May 2015, 12:39

This did the trick for me-

http://volvospeed.com/vs_forum/topic/16 ... so-easyyy/