a/c problem

[cpp]

while out fishing last week, my front a/c quit blowing cold. The compressor is not coming on. Any ideas where to start troubleshooting? They are original Cruisair units on my 78 37C.

 

[Reefgeorge]

with a call for cooling:

1) Is low voltage power being applied to the compressor relay or triac?

2) If so is high voltage power being applied to the compressor?

3) If there are low pressure and or high pressure switches in the refrigerant circuit, are both of them working properly and if so indicating pressure that is out of bounds?

4) If all dead, is there power to the wall controls?

I ammassuming that that older unit has no diplay or codes.

George