Only 80-84 vans have the brake failure warning setup. These use 3 wire
switches to supply the signals to the dash warning module and the rear
brake lights. 85-91 vans use 2 wire switches, only for the rear brake
lights.

For some reason new switch quality seems low and the supply of new 2
wire switches is even lower.

Mark

SDF ( aka ;jim lahey' - Scott ) wrote:
> re this brake warning light module K ...
>.................
>
> Obviously the swtiches , one or both I imagine, turn on the brake lights.
> the 'other function ' is for a legally required brake failure warning light
> in this system I'm pretty sure that if there is a significant difference
> in pressures between the two circuits
> ( like say a rear wheel cylinder is leaking badly ) ..
> the two brake light switches tell this info to the module ..
> the module sees 'no pressure in one side' compared to the other
> circuit.   thus turning on the warning light .
>
>