I have a 2001 Ranger XLT 2.3L auto. About 2-3 weeks ago my wife drove my truck and said that there was just hot air blowing out. I confirmed this when I drove. Turn to max ac and it's just the ambient air or as hot as it is outside.


Back in 2013, I replaced the AC compressor because it was seized. I replaced the dryer, reed valve. Vacuumed the system complete, put in pag oil 46, and then the r132a. It's been fine even though I have had to refill the system/top it off a couple years ago. Which makes me believe there is a leak somewhere...(get into it later).


Thinking it was just the low pressure switch I replaced both that and the high pressure switch. I did not hear the AC clutch engaging at all. And when I temporarily jumped the LP wires the compressor did kick on. After replacing those I ran into the same problem. AC compressor did not kick on. I tried to refill the system even after pulling a vacuum. The vacuum was at -28. It held that for over an hour... So if it does have a leak it's very small perhaps? When I've done this in the past the ac clutch still engages and I am able to fill the system. This time around I could hear the click but didn't see the compressor clutch engage. Not sure what that means.


I did some basic trouble shooting. I hooked up my multimeter to the AC clutch hardness (gray connector on side of compressor 2-wires) while the truck was on and the AC MAX was selected. It only read 0.038 volts. I would think this should be 12v, no? OR Does it only send 12v once the relay opens and the PCM tells it to engage? That's the only thing I can think of why it wouldn't read 12v? I was under the assumption that it that plug should read 12v all the time but I couldn't find anywhere on that information. If I jump the low pressure wires the clutch will engage. I did not take a reading on the harness after jumping the low pressure wires. I will do that today. I would think at that point it's sending 12v to the compressor clutch, but not 100% until I check.


So it brings me to my next point. My truck is 18 years old. It's in good condition minus this AC. Still drives fine (slow mind you since it's a 2.3l auto), but other than that doesn't look it's age at all. I feel like perhaps I should have replaced other components when I did this back in 2013, but at the time I wasn't that knowledgeable in terms of removing all that stuff. Now I am on the mind set that I should be replacing all components. The condenser, lines..etc. Those are all almost 20 years old, original to the truck and probably should be replaced.


I've attached a screen shot of all the components I would get. All motorcraft. It's around $600+ for all the stuff which makes me wonder if I should. I don't want a car payment and I am not interested in buying a new truck. This one serves me well on what I use it for and it's fortunately not a DD so I can have it taken apart in the garage on the lift for however long it needs to be.


Should I be checking other stuff or anything that might be glaring that I am missing?


I will note that when I checked pressure after my wife said there was no AC, the high side showed almost nothing. The low side if I remember correctly was low as well, and when I tried to fill from the low side that gauge rose 70psi..etc. but the highside stayed almost nothing, it only went up 5psi (almost nothing).


My only fear is changing everything in the below screen shot and then having it still exhibit the same behavior as it is now. Note that I would prefer to stick with motorcraft stuff and not have to do said work again.








Sorry for the long read. Just want AC back ;-)

Thanks,
-Nigel

 

In 2001 Rangers the PCM(computer) is part of the AC system
And just FYI...........MAX AC just closes the fresh air vent and recirculates the already cooled cab air, verses trying to cool the assumed hotter outside air
AC systems only have 2 settings, ON or OFF

The pressure switches are the Ground path for PCM to activate the AC Compressor Relay

PCM(pin 86)---------------------pressure switch----------------------pressure switch-------------------------Ground

PCM(pin 69)---------------------AC relay----------------------12v(from PCM relay)

AC Relay is in the engine fuse box(AC Clutch relay)

2.3l may have electric fan, there is an e-fan relay in engine fuse box as well it is also Grounded by PCM when AC is on, so if fan is also not coming on then Ground may be the issue

PCM gets a 12volt signal on pin 41 when cab selector switch is turned to ANY position EXCEPT Vent or OFF
This 12volts comes from fuse 10 in cab fuse box, 7.5amp

So when you select AC in cab 12volts from fuse 10 goes to PCM
PCM then connects the Ground from Pressure switches(pin 86) to AC Clutch relay ground(pin 69)
AC Clutch relay closes and sends 12volts from Fuse 25 to the AC Compressors clutch

Fuse 25 in the Engine fuse box, 10amp
Fuse 10 in the Cab fuse box, 7.5amp

Check these two fuses first, looking is not good enough, test with ohm meter or swap out, "Looks OK" is fine for describing a woman, NOT A FUSE

 

Thanks Ron! You always post the most useful and helpful information!

I will note I did check all fuses both in the cabin and under the hood. All fuses checked out ok and lit up green with my fuse tester. No fuses were blown or broken. Would using my mulitmeter on the ohm setting tell me anything different with those two fuses that the fuse tester did by showing it was a complete path?

Thanks again,
-Nigel

 

No, OHM meter just show 0 ohms when testing a good fuse

You could use OHM meter on the pressure switches, they are grounds when connected and OK, so test from good ground to each switch wire while its connected, should see 0 ohms

KEY OFF
As per drawing I would use jumper wire from battery positive to the Grey/white stripe wire on the AC Clutch to make sure it "clicks" Closed
Then start engine and do the same, to see if compressor starts to spin
The "click" you heard may have been AC Clutch relay, not the clutch itself

If clutch is working I would then test AC Clutch Relay, locate it and then have someone turn AC OFF and ON using the cab switch, while you have a finger on that relay to feel it open and close.
The "click" you heard may have been the Fan Relay not AC relay or clutch

If AC Relay is not working swap it out

But you are down to PCM or no ground from pressure switches
If the e-fan is coming on with AC on then PCM is working OK

PCM does have a few reasons it will not activate AC Clutch Relay
Overheating, 2.3l uses CHT sensor for this but you would have running issues if it was failing
Wide Open Throttle, again there should be a no start or running issues if this was the problem

And never heard of PCM having a problem as far as the AC Circuit
But you can test the pins shown in diagram for 12volt and ground if it gets that far


I use sewing needles to pierce wires while they stay connected, to read ohms or volts