Hello everyone,


I have a 1987 Ford ranger 4x4 that I recently replaced the whole ac system on. However, the ac is not getting any power and I was wondering if it could be fixed? What could be wrong?

 

Welcome to the forum

Compressor clutch is what gets the 12volts to turn on compressor

In 1987 that 12volts comes from a switch on the dash when AC is turned on, it has a Fuse in cab fuse panel, 10amp

That 12volts runs thru a Pressure Switch on an AC hose/line, if the pressure switch is closed(has pressure) then that 12volt runs to the WOT Relay, wide open throttle relay
WOT relay is on the inner fender of engine bay it has a Black Base(plug in)
There should be 3 main relays on inner fender
Green Base, fuel pump relay
Brown base, EEC relay
Black base WOT Relay

WOT relay passes that 12volts to the Compressor Clutch, when relay is OFF, so its a 5 pin relay
WOT relay is only used at Wide Open Throttle(pedal to the metal), computer turns ON this relay which cuts 12volts to compressor to turn it off so driver has ALL available power to pass or ???
Also turns relay on when starting the engine

So key on engine off, test if you have 12v at the compressors 2 wire connector
Also test with engine idling
If so but no AC then clutch coil may be bad, test it with OHM meter, 2 to 5 ohms is OK

If no 12v
Pull out WOT relay and test its base slots for 12volts, should be TWO slots that show 12v
If so then replace relay

If only 1 slot has 12v
Locate the Pressure switches 2 wire connector, unplug it, one wire should have 12volts
If so replace pressure switch, you don't need to drain the system, pressure switches can be swapped "hot"

If no `12v at the pressure switch then you are in the cab now at the dash switch, pull it out and test wires for 12volt

Fuse---------dash switch--------------pressure switch------------WOT relay------------------AC clutch

 

1987 ford ranger xlt help. The relay for the ac has been replaced, and it still has no power to the compressor at all. The fuse is good and the compressor and ac system are brand new. What could cause the new relay to have no power at all?

 

So none of the slots on the WOT relay base show 12volts with key on?