So I am installing A/C in my 92 ranger as I am tired of no A/C...that and I am fat so yeah.

Anyway, here are the parts that I got:

Compressor
Condensor with all lines
Evap box with accumulator (got a new accumulator coming)
Control panel
All pigtails that were plugged into the A/C, including A/C relay.

Question is, I've been reading that these trucks have all the plugs already there, its just a matter of plugging them in and go. However, I cannot locate any of those plugs. Are there write ups that I am missing on how to wire everything up. I am not afraid to wire it up, I just need to know what goes with what so it functions properly.

 

After spending an hour looking at the wiring schematics, it looks like on the 4 cylinder there is no pressure cycling switch. This means that the compressor is on all the time when the a/c is turned on. Does this seem right? If so wiring this up is cake as all you need to do is use the low pressure switch as a ground for a relay, and the a/c switch inside the cab to activate the relay, and your out put out of the relay would be the a/c clutch. However, the 4.0L models shows that it has a pressure cycling switch, my guess is that the bigger motors had different size pulleys so on a 4 cylinder you won't over pressurize the system by running it all the time.

So now I just need someone whose had experience with this to verify my theory and I'll be set. I also need to wire in the purple wire into the PCM but that's cake.


Forgot to add, that on all the donor parts I have, there is only a low pressure switch on the accumulator.

 

It sounds like it is an expansion valve system so it will stay on most of the time, it will cycle eventualy just not to often. I could be wrong though, If you have a cylcle switch in one of the lines you will have to find were the connector is for it.

 

The system has an orifice tube, that I only have a low pressure switch sitting on the accumulator. Other than that, there isn't anything else in the system.

 

The low pressure switch on the accumulator is the cycling switch.

 

Thanks. I spoke to a Ford tech today and that is what he said as well. He told me just wire up a relay for it and call it a day, just make sure the switch acts as a ground for the relay so once it activates it shuts the relay off. So now all I need is a day off and get this thing going.

 

I figure I will update this for future reference. This is on a 92 Ranger, so locations of things may be different on other years.


Everything is literally plug in play minus the compressor relay. The harness for the heater controls already has the two purple wires, which one runs to the ECU and one to the compressor relay plug. Basically transfer over all the A/C components onto your truck, and everything will plug right in. On my 92', the compressor relay control plug was chilling under the power distribution box on the passenger side well. If you look at schematics, all the wiring on that plug are for the relay, aka constant power, switch 12 (from switch), ground, and wire to the clutch itself. If you're wiring in a relay yourself, you need the purple wire off that plug to trigger your relay. To wire it up so the low pressure/cycle switch functions, purple wire from the plug goes to the purple wire on the switch harness. The other wire off the switch goes to your relay. So once the switch breaks the circuit,the relay kicks off and compressor kicks off.

This is a pretty vague description but hopefully it helps someone in the future.

P.S. If you're just snipping off the pigtails for the components at the junkyard, be sure when you're getting the pigtail for the compressor, trace the wires because this harness has diodes in it. The diodes prevent voltage spike in the system, without them, you're risking frying your electronics. So watch out for them and make sure you snip away with them still in tact. The diodes cross over from the positive side to the negative side aka + to - .