[Don Higgins]

Town cars don't have an air front suspension. Only the Continental and Mark 8s have these.

I would jack up the body then turn on the air suspension. Spray the bags and lines with soapy water and look for leaks. Probably the bags and if so your options are somewhat limited.

I have located the air line before, hooked a compressor at about 20lbs pressure and found the problem quickly.

It is extremely rare to have a controller issue or solenoid problem. It is leaking somewhere. The compressor can only run so long before it shuts off because of heat.