Brake Light Switch on a 1999 Volvo V70
Detecting a problem with the brake lights on 1999 Volvo V 70 Classic (North American Edition) is easy, especially with the help of our friends at http://www.volvotips.com/
If your light bulbs and fuse are OK, the problem is most probably the self adjustable brake light switch located at the top of your brake pedal. The problem in 99% of cases is there and not in your relay. BTW on the North American Classic model the relay is NOT in the trunk compartment (neither left nor right side, since they are empty) but behind your radio. Start messing with the relay ONLY if you are sure, the problem is not in the (1) fuse, (2) bulbs or (3) the switch.
The brake light switch on the 1999 Volvo V 70 is a fairly simple device fabricated by Volvo to activate your brake light when the pedal is pressed and deactivates when the pedal is not pressed, in which position the pedal and the switch actually touch.
The most probable reasons why your switch is failing, is the small white cylinder which provides the adjustable part of the switch. Often, if you press on the pedal with one hand, you can adjust the white adjustable cylinder with your other hand for a (temporary) fix.
In most cases, however, the small tracks on which the white cylindrical adjuster moves ware out and cannot be restored. The safest thing to do is order a new one at about $40-50 at any auto part store. We got ours at Advanced Auto Parts which has always been helpful in diagnosing our problems. The replacement of the switch is shown on the following picture (and yes, it is possible to remove the switch without breaking it):
It is also possible to take the switch apart. In our situation, the switch had started to fuse together at the two metal points which provide the actual contact for the electric circuit. Yes, you could brush it and clean it to be reused, but do you really want to do that at the risk of your brake lights not working (which BTW is illegal to drive with in North America).
Ok so I took the switch out and took the thing apart and found that the contacts where pitted so I took a fine file and cleaned them also stretched the springs a bit that seemed to do the job. This page was very helpful I will now try and take my switch out and see what I can do with it.
Thanks again