Brain Trust Help needed on Parking Brake Light, Parking Brake Light Always on...... Options

[Gatornapper]

Once again need the help of the great 914 Brain Trust here........

My Parking Brake Light stays on all the time.

The switch is fairly new and it is functioning properly.

Disconnecting the brown (ground) wire to the switch, it has no continuity or resistance to ground. So it is not "grounded out" somewhere.

I see in my great 914 electrical schematic of the ground circuit for the switch and light that there are two diodes in the circuit.

I am guessing that one of them failed.

Can anyone tell me where these two diodes are located?

Or where else the problem might be?

As always,

TIA,

GN

[Literati914]

I’d say ‘don’t be surprised if there is no reset button to push’ … I have 3 old 914 master cylinders and none of them have a reset button. Am I missing something? They all have some type of a square plastic “tower” where the spade(s) are … is that somehow the reset “button”? I lightly tried prying the plastic block off on one and that didn’t seem to be the case (IMG:style_emoticons/default/confused24.gif)

Not all switches have the latching function and the reset button. The later model two pole switches are not latching - when there is a problem in the master cylinder the pressure differential between the hydraulic circuits will cause the light to turn on.

If you’ve converted from an early single pole to double pole switch (or vice versa) it needs to be wired accordingly.

My car came with a separate ground wire at the MC input - this is the only reason I switched from the single pole unit (which has an obvious button to push) during installation, besides already having one on hand.

So, as for the single pole switches like I posted above and you posted in the other thread (showing MC internal workings) - how do they get reset?