I have a 2001 s-type 4L. The air conditioning does not work on this vehicle. It blows ambient temperature (not hot) air only. (The climate control valve was already replaced this winter).

Checked the refrigerant. The pressure was real low. Put a little more into the system but it seems like the refrigerant was not circulating even when the AC was turned on because I could only put a small amount of refrigerant in.

Checked the fuses and they were ok.

I noticed that the compressor clutch was not engaging but could freely spin by hand. I took the relay out and put a paper clip in. This succeeded in engaging the compressor clutch.

The refrigerant pressure didn't go way down like it should have if the compressor were circulating the refrigerant. Instead, it only went down in pressure a little and it went back up to where it was to begin with when the car was turned off.

Also, I noticed that the cooling fan did not turn on when the AC was on. I didn't see a separate condenser fan.

There are no engine codes showing up and I noticed in the Jag workshop manual that there are several codes related to the high and low ac pressure sensors.

Does anyone have any ideas about this problem? Thanks.

 

Hey, I fixed the problem. I just put more refrigerant into the system. I do not know why the small amount of refrigerant I had in it before was enough to activate the compressor clutch. Adding more refrigerant didn't increase the low side pressure. Maybe there is another interlock or something preventing it from turning on the clutch withount enough pressure on the high side. I read the workshop manual and there is a high side interlock but it should allow activation so long as high side pressure is less than ~500psi.