The Rodding Roundtable
Motorhead Message Central => Rodder's Roundtable => Topic started by: zzebby on July 10, 2009, 12:33:16 AM
I am wiring up the a/c circuit from scratch, 71 Ford pickup with 5.0 L Mustang engine and the late model a/c compressor. I have +12 volts from the fuse box to the blower motor rotary switch then to the evaporator thermocouple switch and then to the coil of the relay. Other side of relay coil is grounded. The main contacts of the relay send fused +12 volts to the clutch on the compressor. I'm sure of all this so far.
Question is........what about the cycling or pressure switch in the freon line ? If I wire it into the coil side of the relay then the relay is constantly opening and shutting and will wear out. If I wire it into the load contacts of the relay then the cycling / pressure switch sees all of the clutch coil current. How much current does the clutch coil draw ?
What would you do ?
Normally they are wired into the clutch circuit. If you have a concern, you can wire it to operate a second relay so the pressure switch will only see the relay as a load.