At 09:38 PM 7/24/2001, Chuck Hill wrote:
>Symptoms & observations:  When the van sits overnight, the condition
>goes away, but returns when the brakes are applied normally once.

Ah Ha!  Your brake lights are working fine -- the hydraulic pressure in the
system isn't releasing properly.  It bleeds off overnight, but when you
step on the brakes again, bingo.

>The
>braking action is normal as far as I can tell during normal driving.
>Disconnecting either brakelight switch on the master cylinder doesn't
>shut off the brake lights, but if both switches are disconnected, then
>the brakelights go off.  This condition remains even if the brake
>warning light module is unplugged, removing it from the circuit.  I
>haven't yet checked for continuity through the brakelight switches, but
>I suppose they must be "made" to light the lights.

Forget the electrics and troubleshoot your hydraulic
problem.  Unfortunately I don't know anything about it...except that
apparently the pressure is being maintained in both circuits, which
suggests a brake pedal or master cylinder problem to me.

>Why are there two brake light switches anyway?

Because there are two hydraulic circuits, each operating the brakes on two
wheels.  That way a catastrophic failure of one circuit will still leave
you with some braking ability.

david

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"