[Top] [All Lists]

Re: Brake wiring 80B

To: David Wilkinson <>
Subject: Re: Brake wiring 80B
From: Wayne Kube <>
Date: Sat, 21 Dec 1996 16:15:04 -0600
David Wilkinson wrote:
> Hi, I'm appealing to your collective wisdom to help me sort out my brake
> light problem on my 80B. The brake lights don't work. All other electronics
> seem fine - except my headlights brighten and dim with engine speed.
> Anyway, when I look through the moss catalog, I see a brake switch - which
> I can't find on the car!, and a pressure failure switch on the master
> cylinder - which I can find.

David -
        The brake switch is located on the rear of the pedal box - between the
box and the firewall.  It is positioned next to the clutch master
cylinder.  The switch should have a green and a green/purple wire.  The
green wire is switched 12 volts - only on when the ignition switch is
turned on.  That green wire gets its power from a fuse in the fusebox. 
Check the fuse - if good, the other end of the fuse is 12 volts from the
ignition switch relay (this is the front-most relay, not the starter
relay).  The 12 volts from the relay to the fuse is on a white/brown
wire.  The second wire on the brake light switch is green/purple - it
sends the 12 volts to the lamps.  The pressure failure switch on the
master cylinder only lights the warning on the dash.

        If all of the above checks out - and you have good bulbs - look for a
bad ground.  Rear ground is from the bolt on the back of the license
plate mount inside the trunk.  The brighten and dim on the headlights
could indicate a poor ground, poor voltage regulator on the alternator,
or very likely corroded connections on the bullet connectors.

Happy Holidays - take an MG for a drive on the 25th!
Wayne Kube
Plano, TX

<Prev in Thread] Current Thread [Next in Thread>