2001 Explorer with 4.0 SOHC engine

Bought the truck last winter. This summer found AC inoperative. The clutch would not engage for any control setting.

Jumpered the low pressure cut-out switch (on the accumulator) and the compressor engages and runs.

I don't have the dual set of a/c gauges. I realize I can get a set on loan from an auto parts store or buy a cheap set, but right now I can't spend a lot of time on this.

I used an R-134a recharge can with the small gauge on top. Half the can (about 11 oz) recharged a small car we own. Then I connected it to the Explorer low pressure port (above the accumulator) and with the engine running, the remaining half can (about 11 oz) slowly went into the a/c system. When first connected, the gauge read zero (on the small car it read something like 10 psi). As the refrigerant was drawn into the Explorer a/c system, the pressure went up a small amount, maybe to 5 psi or so, then dropped down to zero.

I hooked up a second can to the Explorer. This time I jumpered the low pressure cut-out switch to try to draw the refrigerant in. Engine rpm was held at 1500 rpm. I only got about another 14 oz into the system, and that required holding the can upside down a lot of the time.

The tubing and bracket the low pressure port is on frosted up. Looking down on the accumulator, it frosted up 3/4 of the way around the circular shape. The low pressure line coming out of the accumulator frosted up for a few inches near the accumulator.

But the low side pressure stayed right near zero.

With the jumper removed, the compressor would still not engage.

What do I do next?

Is the accumulator plugged and the refrigerant leaking away?

Is there probably some massive leak?


I realize I could take it to some a/c mechanic, but it's an old truck I got for my son, and I'm not able to spend hundreds or thousands on this.

Thanks in advance for your thoughts and advice.