You got It right most likely. A short of the wire going to the pressure
switch. The switch is behind the tin cover that is on the driver side under
side of the engine. You can see a heavy brown wire going into this from the
rear of the engine.The wire connects to the switch.Maybe try wiggeling the
wire while the engine is running to see if this is the problem.161K is real
good. Should get many more out of the wbx.