A/C not working, Compressor comes on when jumped

Hi all, my A/C hasn't worked since I bought the truck. I've jumped the compressor at the low pressure switch on the accumulator and the compressor kicks on. The system will not take freeon. What do I need to do?

Like putting power to the switch or jumping the 2 pins to each other?

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Start with a new switch, if that doesn't fix it roll down a window.

^^ This unless you have the knowledge and means of repairing an AC system. I'm learning as I go with my Bronco 2 and taking my time reading a lot and re-reading. Very interesting and I read somewhere that you think you know about AC but you don't. Its very true. Tons of great information in the tech section of this forum on the AC system, how it works, and how to repair it very carefully and how to do it the right way. We all see those recharge cans at the stores with the little dial gauge...those things are garbage and spell disaster to your AC system as you are only getting 1/2 the information on that one gauge, not to mention most have leak sealants which most likely will plug up your orifice tube and everything else but not the real leak. Best to do a full system evacuation and start at the beginning in an unknown system or any system for that matter.

The PO of my Bronco 2 did tell me the compressor failed and was replaced, but the system was never evacuated, flushed, and repaired beyond the compressor replacement.

JamesH said:

Like putting power to the switch or jumping the 2 pins to each other?

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Jumping the 2 pins together with a paperclip. The compressor took freeon and air blew kind of cold but then stopped. Been while, summer is back again.. still trying to get this fixed. Thanks.

Because we aren't there looking over your shoulder, any and all information possible should be coming from you. what was the outdoor temperature? what was it that gave you the idea the sys wouldn't take refrigerant? How long did you run it on the paperclip?

Mhfco6 said:

Hi all, my A/C hasn't worked since I bought the truck. I've jumped the compressor at the low pressure switch on the accumulator and the compressor kicks on. The system will not take freeon. What do I need to do?

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Denisefwd93 said:

Because we aren't there looking over your shoulder, any and all information possible should be coming from you. what was the outdoor temperature? what was it that gave you the idea the sys wouldn't take refrigerant? How long did you run it on the paperclip?

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The compressor was dry and wouldn’t kick on so I ran it on the paper clip long enough for it to start sucking refrigerant. Once it started I took the paper clip off and it ran on its own. Was about 87* out.

Do you have a pressure gauge? Read the pressure without the system running tell us what that is and what the outdoor temperature is at that time. Static pressure should be equal to the corresponding temperature on a TP chart

Mhfco6 said:

The compressor was dry and wouldn’t kick on so I ran it on the paper clip long enough for it to start sucking refrigerant. Once it started I took the paper clip off and it ran on its own. Was about 87* out.

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Denisefwd93 said:

Do you have a pressure gauge? Read the pressure without the system running tell us what that is and what the outdoor temperature is at that time. Static pressure should be equal to the corresponding temperature on a TP chart

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Yes I have a gauge, been a year since I tried.. the system is probabaly dead again. I will PM you my findings. Thanks for your help!

Take pictures I'm not the "expert" when you start the system if it's low on refrigerant the compressor will go on and off rapidly or not at all, it will also short cycle with the proper charge and it's not hot outside.

Mhfco6 said:

Yes I have a gauge, been a year since I tried.. the system is probabaly dead again. I will PM you my findings. Thanks for your help!

Click to expand...

Denisefwd93 said:

Take pictures I'm not the "expert" when you start the system if it's low on refrigerant the compressor will go on and off rapidly or not at all, it will also short cycle with the proper charge and it's not hot outside.

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The gauge reads 0 at 80* outside ambient

0 = no refrigerant. A properly charged system that is not running at 80 degrees ambient should be about 86.5 psi

Mhfco6 said:

The gauge reads 0 at 80* outside ambient

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Denisefwd93 said:

0 = no refrigerant. A properly charged system that is not running at 80 degrees ambient should be about 86.5 psi

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Bingo! Like I said.. I had to jump the plug in order to start compressor. Refrigerant was so low the compressor wouldn’t turn on any other way.

Mhfco6 said:

Bingo! Like I said.. I had to jump the plug in order to start compressor. Refrigerant was so low the compressor wouldn’t turn on any other way.

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Yea theres an extremely good reason the compressor wont come on with no refrigerant in the system. No refrigerant means no oil... Chances are by now, sitting with no pressure for a year (or god knows how long) and having the compressor run without oil, the system needs way more work than a evac and recharge. Its a broken, neglected 27 year old AC system. Cut your losses and roll down the window.

Dirtman said:

Yea theres an extremely good reason the compressor wont come on with no refrigerant in the system. No refrigerant means no oil... Chances are by now, sitting with no pressure for a year and having the compressor run without oil, the system needs way more work than a evac and recharge. Its a broken, neglected 27 year old AC system. Cut your losses and roll down the window.

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Correct, had to jump it to start pulling fluid in. Compressor squealed like a pig. Figuring bad compressor, what else do you think I should take a look at? Thanks for your help!