Those aren't electrical switches on the 2 pedals on the factory cruise
setup.  They're vacuum release valves, in parallel with the cruise vacuum
actuator.  When you step on either pedal, you're basically opening up the
vacuum line to the actuator.  When it loses vacuum, it can no longer keep
pulling the diaphragm (along with the throttle linkage).  This trips the
"set" off, until such time as you re-set it back on.  Automatic and
instantaneous disengagement of cruise control.  Aftermarket cruise does not
work the same way.

HTH,
Mike B.

----- Original Message -----
From: "Todd Last" <rubatoguy@COMCAST.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, April 10, 2007 1:49 PM
Subject: Re: Brake light sensor switch adj.

> On my Vanagon (88) there are switched on both the brake and clutch pedals
> for the cruise control.
> I know this because they are the most common point of failure for the
> cruise control when it will not engage.
>
> Perhaps they made a design change for '89?
> Or do you have an automatic?
>
>
> Todd
> '88 Westy
>
> -------------- Original message ----------------------
> From: Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
>> The brake light switches are on the master cylinder and only turn on the
>> light when they see pressure.  If you pump the pedal a lot with the
>> engine
>> off, the vacuum booster will stop working, making it harder to build up
>> the pressure that turns the lights on.
>>
>> I've thought of putting an additional switch on the pedal, in parallel
>> with the stock switches.  The main reason I would want that is so that it
>> is easier to disengage the cruise control.  Now I have to really push the
>> brake pedal until the brakes actually start slowing the van down before
>> the CC disengages.
>>
>> Edward
>>
>> > Many thanks to those who helped me out with my radiator fan question.
>> > I'm
>> > now on to the next project in a row. I just installed a third brake
>> > light,
>> > and in the process of doing the wiring had to press the brake pedal to
>> > the
>> > floor many times. I noticed that the brake lights are not coming on
>> > until
>> > the pedal is fully depressed, which is not a very good thing, and
>> > invites
>> > a rear end collision.
>> >
>> > I looked around at the floor level behind the pedal and did not see any
>> > switch. I also checked the brake section in the Bentley, but did not
>> > see
>> > any mention of a brake switch. Perhaps I'm looking in the wrong place,
>> > and
>> > should be looking in the electrical section? Anyway, how does one
>> > adjust
>> > the switch, so that the brake lights come on sooner? And two, where the
>> > heck is the switch?
>> >
>> >
>> > Thx,
>> >
>> > Troy
>> > 89 Westy
>> >
>