P30 chassis wiring question
All I know for sure is that the chassis manual (which appears to have been published in 1992) specifies the switch as in my post above. The diagram of the switch calls the actuator a plunger, which would indicate to me that it is probably not vacuum operated, but that is a presumption. I'll check at dusk when the temps inside the vehicle go down a bit. I checked the vacuum hoses for dry rot a few days ago, but I did not trace down their entire length.
Thanks for your question