A/C compressor not cycling

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72_dart

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I have a 72 dart with a slant six and factory a/c the compressor isn't cycling. Last summer it was fine. I drove it a little in the winter so obviously I didn't use the a/c this summer no air. What would cause the compressor not to cycle? And how to test the parts that may cause this. If its just the freon being low I'll just wait until I put in a freshly rebuilt heater box with a new heater core and a good evaporator. Any help is greatly appreciated.
Thanks, John
 
When you say "isn't cycling", do you mean the compressor comes on, but does not shut off, or the compressor does not come on? If it does not come on, jumper the presure switch on the drier. If it now comes on, it is just about out of refrigerant. If it still does not come on, you will need to trace the wiring, to see what the problem is.
If the compressor comes on, but does not "cycle", does the air out the ducts get cold? If it gets cold, probably a bad clutch cycling switch. If the air does not get cold, refrigerant is low.
 
Sounds like it's low on Freon to me.

The cheapest source for original r12 I have found is on ebay , there are 100's of original cans people sell on there.
 
It doesn't come on. I wasn't sure where to start. I was thinking that the compressor clutch was bad but I don't know where to begin the diagnosis. Thanks Charlie I'll try to jumper that switch. I'm just going from memory but the dryer has 2 connectors correct? And your talking about jumping those 2 connections correct? Thank you by the way.
 
Download yourself a manual, FREE

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617

http://www.mymopar.com/index.php?pid=31

The AC electrical diagram is not in section 8, it's in the "heaters and air conditioning," section 24

Read starting about page 24-50

Wiring diagram is page 24-52

Look at what you've got. Look at the bottom of the fuse panel, very bottom of diagram. There are TWO fuses, one for blower, one for clutch. So the clutch circuit can quit and the blower will still work. Start with that fuse and make sure you have power there.

Then, power goes through the switch, through the thermostat, and through the low pressure switch to the clutch
 

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Right on. That's cool I checked the fuse.... Well I didn't test the fuse but it wasn't visibly bad I'm pretty sure that it was marked a/c I noticed that there was one for the blower as well. But the diagram will help a lot thank you.
 
72_dart said:
Right on. That's cool I checked the fuse.... Well I didn't test the fuse but it wasn't visibly bad I'm pretty sure that it was marked a/c I noticed that there was one for the blower as well. But the diagram will help a lot thank you.
Click to expand...

Don't trust your eyes with fuses. Always use "at least a light" or a meter. Check on both sides. Fuses can "blow" up in the caps where you cannot see them. Usually, when they fail in that manner it's because of HEAT in the clips caused by loose or corroded connections or bent clips
 
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