cruise control switch.
there are brake and clutch pedal ( if manual trans ) switches for the cruise
control system , with vacuum lines on them, I believe.
if I had stuck on brake lights I'd go right to the switches on the master
cylinder to start with ..
unplug one or both of those to start with.    Pretty sure brake light
voltage goes through there.

cruise control can do weird things though.
as simple a thing as an incorrect brake light bulb can confuse it.
if there is a basic way to de-arm cruise control...like pull fuses for it ..
I'd do that too until the whole thing is figured out.

I suppose a stuck-on brake light switch on the master cylinder is possible,
though I have never seen that actually.

Scott
www.turbovans.com

----- Original Message -----
From: "John Rodgers" <inua@CHARTER.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, August 11, 2010 4:29 PM
Subject: Mystery Switch

>  On my 91 Carat (auto tranny) there is mounted below the dash, that is
> actuated by the brake pedal arm. It is not one of the brake light
> switches - they screw into the brake master cylinder itself, but this is
> actuated by the pedal action itself. When the pedal is at rest (no
> brakes applied) the pedal arm pushes the switch "In", when the pedal is
> depressed, the action is to release the switch. It has one elctrical
> connection n one end, and it appears to have a vacuum hose attached to
> it as well.
>
> I have not been able to identify this switch in the Bentley, so would
> anyone have any idea what this is - and where to find it in the Bentley
> in the event I missed seeing it somehow.
>
> I have brake lights stuck "ON" and cannot turn them off without
> disconnecting the battery. I suspect this switch is a brake light switch
> and it the culprit, but I  haven't for sure identified it yet.
>
> Thanks,
>
> John
>
> --
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, AL
> Http://www.moldhaus.com