[dannymarilyn]

Any chance mechanic accidentally unplugged a connection?

Well, anything is possible, but all he did was drain the coolant, and remove engine temperature sensor on passenger side that drives gauge in dash.

Brake air builds up just fine. Usually over 70 psi, it would begin pressurizing the supply air system. That connection is not happening now. We do not hear any leaks of air.

I did have him drain and refill genset coolant as well, so it did work. Now the genset will not extend because of a lack of air pressure, so the gauge
appears to be correct.

A diagram or schematic of supply system would be most helpful! Thanks for looking!
Danny