Anyone know the inner workings of these VAG brake switches?

Got a VW crafter here throwing up a Brake light Switch F lower limited not reached and implausible signal. It’s come to me after a replacement switch hasn’t cured the issue (no brake lights). Load tested the four wires up to the ABS module, all good. Can’t seem to make sense of the reference signals the module is using though, bridging a couple of the pins causes the F high (ON) and F low (OFF) to flip in the live data but the switch itself does nothing, may as well be unplugged.

I don’t want to condemn the module or the switch without understanding the parameters the circuit should have and how it operates. OEM information is typically unhelpful, just ‘continuity test the wires’ Thanks in advance guys ✌️

4 comments

Anyone know the inner workings of these VAG brake switches?