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MG MGB Technical - intermitant brake lights

I am having a problem with my brake lights. They come on when brakes are first applied but don't after that unless I press the pedal a couple of time. Sounds like a bad brake switch, but I could not locate the switch to test it.

Exactly where is it located?

Vincent
Vincent

What year is your car? On early models it is in a cross tee fitting in the brake lines where they branch out. On the dual circuit brake North American models it is on the housing immediately in front of the master cylinder. I had a similar problem with the later switch on my 69B. The plunger contact was quite well worn. A new switch wil cure it.
Andrew Blackley

Sorry,

1980
Vincent

Vincent. Look at the back of the pedal box assembly. There are two wires running to the brake light switch. You will have to remove the top cover of the pedal box to get full access to unscrew the switch. Also, check the wiring connectors to make sure they are clean. I also believe that fuse number four is part of this circuit and if the fuse clamps are not clean or you have the wrong fuse in there, it will affect brake light operation. Les
Les Bengtson

Green and green/purple wires. Depends how you number your fuses but it is the 2nd one up from the bottom. However if that fuse is playing up it affect all sorts of other things including gauges. Sounds like the switch itself is bad as if simply badly adjusted they will stay on all the time. When replacing the switch you need to make sure that it is screwed in far enough to cut the lights when the pedal is released, but not so far that it stops the pedal coming all the way back or you can get the brakes sticking on.
Paul Hunt

FYI:

I had a slightly different problem with my 73 but the brake lights stayed on after I first applied. I went as far as guess that the brake switch was intermittently failing and replaced it. I'm not too sure of the differences between our cars but my fix ended up being an easy one. There is a return spring which mounts to the brake pedal and mounted up underneath the dash, I found that throught the years this spring had stretched (possible due to disconnecting the brakes during a rebuild) I just bent one end of the spring a bit and taadaa, no more issues. It ws just the spring wasn't strong enough to properly seat the brake switch to turn the lights off.
EJW Willis

This thread was discussed on 12/04/2002

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