compressor not kicking on

[aricanderson]

Ok I have a 95 Explorer that I just bought and have already fixed the vaccum leak causing the air to blow through the vents again. Now I noticed that the ac is not cold, nor is the ac compressor cycling on or off, or the engine reving up. I took the pressure readings today and got 50psi on the low and high side. So I took a jumper and shorted the cycle switch and the compressor kicked on and the low pressure side started pulling a vaccuum. No my question is do I need to replace the cycle switch or do I need to vac the lines and charge the system with new freon, or should I just try adding more freon. Do you need to discharge the system to replace the cycle switch?

95 Explorer
low side: 50psi
high side: 50 psi
outside temp: around 60 degrees F
humdity: around 70%



thanks
aric

 

[KPT]

There is not enough refrigerant in there if its pulling a vacuum on the low side.

The switch can be replaced without discharging the system. There is a valve in there. The switch is not the problem though...

 

[aricanderson]

update

i pulled the cycle switch off and tested it with my compressor and ohmmeter and found out that it works after adjusting the screw on the switch. Then I put it back on the ac system. Now the compressor cycles on and off. The low and high side start at 50psi. Then the low goes down to around 10psi while the high goes up to around 100psi. Its hard to tell if the ac is cold because of the weather temp outside. Although I believe that I will try to put in a can and see what happens. How do you know when the system is fully charged? Can the ac system develop leaks at a higher pressure then what its running now. I'm just wondering if i should vac, then charge it back up or just try a new can. Because it seems like it holding the 50psi.

 

[ma96782]

I'm ASSUMING that you're talking about the pressure switch (w/screw) on the accumulator?
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IF that is so......well, I wouldn't have fussed with the pressure switch setting, before re-charging the system. That's ME.
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So.........now that you have fussed with the screw on the switch.

May I suggest that you got get it re-charged. Don't forget to tell the mechanic that you fussed with the switch setting. He'll probably replace it rather then playing with it. His time is valuable.
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IMHO.......next time........re-charge it first.

The setting on the switch doesn't need to be fussed with (it's factory set).

Aloha, Mark

PS...........IF you have the equipment and knowledge, pull a vacuum and start all over from the beginning. Play with the switch setting all you want. It's your time. Or, replace it. Again, that's ME.

 

[BrooklynBay]

Never tamper with the factory setting of a safety switch! It's doing its job by cutting off the system because it's low on freon. That's what it was designed to do.