I recently purchased a used 2003 Excursion. Having an A/C issue and had a quick question. I checked the charged and pulled out only 1.2 lbs. so I charged with 2 lbs of r134 and nitro tested system for leaks. Found a small leak on suction line, replaced seal. Went through the whole recovery vacuum procedure. System held 30 inHg of vacuum for 25 minutes. So I recharged system with 4 lbs and 4 oz of Freon. With system charged in showing high suction and low discharge pressure on gauges... both at about 100 psi. I checked the compressor, compressor is ok, but doesn't engage. I can spin the clutch by hand and pulley is turning with belt just fine. No clutch engagement obviously because of missing power to compressor. So next step is the orifice tube, but I just wanted to know if there is some kind of a climate control feature built into the electronics controls to prevent the A/C from working. It's 65 degrees in the shop so I just wanted to make sure. Thanks

Rafal

 

Leave the O-tube alone until you figure out WHY the clutch isn't engaging.

Why is it obvious? Nothing you said would make it so.

There are about 10 things that can go wrong to keep the clutch de-energized.

Unfortunately, there's insufficient information provided to go into the diagrams properly. Need to know which engine and which climate control system is installed.

 

Ok sorry for the lack of info. Actually found a short for the high pressure switch that was causing the issue. Tried jumping it and it didn't help, so took the harness apart and found a broken wire right by the plug.

I have a v10 Excursion with rear evaporator...


All my A/C experience is with semi trucks and I ran into issues before with International where the clutch on the compressor wouldn't engage below a certain ambient temp, and the ambient temps sensors seemed to failed on those, so I just wanted to see if this was a similar case.

 

If you had a broken wire, it was an "open" which is exactly the opposite of a "short".

Generally, the A/C system won't work below 40-45°F due to the P-T curve and the set-point of the low pressure switch. I have no idea if a EATC-equipped system (have no idea which control unit you have, you still didn't say) uses the ambient temp sensor as an input to its logic. I've never seen any reference or occasion that would lead me to believe it was.

 

Ok thanks for the help. I didn't realize there were multiple control units on these trucks.