If anyone can help me out here, I'd greatly appreciate it.

First, some background. I bought this truck two months ago, it's an 88 regular cab with the 2.9l V6. The only problem I have with it thus far is the air conditioner, and I've pretty much got the problem traced down, but I don't know what part I'm looking at. The a/c button in the truck lights up when pressed, so it's got to be power to the compressor.

The culprit, that I've identified with my limited experience, is the wiring leading from the compressor (activating the magnetic clutch) to something on the left side of the engine bay (when standing in front of the truck itself). I pulled a small length of wire from the plastic tube, and it seems someone did a nice hackjob on it, as this stuff doesn't look necessarily stock, with old electrical tape abounding on it.

If anyone knows what I should ask for when visiting the local dealer, please let me know!

Thanks!
--Chris

 

I don't know anything about Rangers. But would expect your A/C to be the typical Ford fixed orifice system, with a cycling pressure switch on the accumulator. Electrically in series with the compressor clutch is the cycling pressure switch. When the A/C is on, it's job is to turn on and off the compressor, governed by the system pressure, therefore, the temperature. In a fixed orifice system, the cooling amount is fixed. Without cycling it off at the appropriate temp, it would overcool and freeze up the evaporator core.
A side benefit of this system is that the cycling pressure switch is OFF at less than 22 lbs psi or so. This is used to prevent system startup with insufficient charge. Normally, with the A/C off, the suction and discharge pressures equalize somewhere in the middle, well over the 22 lbs. That allows the switch to be on, sending current on to the A/C clutch when you flip the switch. You may be low on charge, switch open.
You can TEMPORARILY unplug the connector to the cycling pressure switch, and jump the harness end contacts together with a unbent paper clip. Then see if the compressor can engage, and if so, if it cools. If it does, the cycling pressure switch may be bad, get a new one and unscrew the old one. Has a Shrader valve, so gas won't be lost when you change it. But if it ran, and didn't cool, turn it off and remove jumper, don't damage compressor by running it that way for any length of time. You don't have a charge in that case, find and fix problem properly.