I need some help. The compressor in my 01 XLT cycles on for 5 seconds & cycles back off for 10-15 seconds. I know it's not low on refrigerant or oil because I just evacuated the system down to 260 microns & then weighed in the required amount of refrigerant less than 24 hours prior to the time stamp on this post. I would appreciate more help than my last 3 posts which have still not been answered after months.

 

In 2001 the AC clutch relay is controlled by the computer(PCM)
It grounds the relay to activate it

12v key on---------AC relay coil---------------computer pin 69

The 2 pressure switches supply the Ground the computer uses

Ground----------switch 1------------switch 2--------------------computer pin 86

So there is a relay inside the computer that connects pin 69 and pin 86 together when you "turn on AC" in the cab, the "demand signal" 12volts to computer pin 41

Cycling can be a few things, most common would be the pressure switches
If pressure gets too high a hose or fitting can rupture
If pressure gets too low then compressor can run dry and burn up
You can use a volt meter or test light hooked to Battery positive, and test each wire on a switch while its connected, use sewing need to pierce wire, all 4 wires should be a good Ground AC on
If you are losing the ground during cycling then switch is opening, but doesn't mean switch is bad, it could be opening because of high or low pressure

You can hook up pressure gauges to see if a pressure switch is bad, i.e. opening at the wrong pressure
Clogged orifice tube can cause higher pressure or lower pressure

2nd common thing is the Clutch "air gap", the AC clutch on compressor is an electro-magnet, when its has 12v and ground it pulls the clutch plate in and compressor is engaged
If the gap between electro-magnet and plate is too big then it can't hold the plate in, so on and off cycling
But easy to test for that, just use a 12v test light or volt meter on the 2 wires at the Clutch, if you see 12v power but compressor cycles off then its an "air gap" issue
If the 12volts is going off then AC Clutch relay is turning off

 

First, I apologize for the delay. Second, I appreciate the help and the diagram will come in very handy. I don't know what this means, but the compressor remains running when the engine is at 2000 - 3000 rpm. Unfortunately, I haven't had time to go digging around under my hood, but today (3/23/23) is the 1st day it has been warm enough to use my A/C. I will keep posting to this thread to keep you up to speed on my findings.

Thank you again,

Scott