ok, so I have been so happy to have gotten my truck running that I have been driving it everywhere I go here in Texas. Was out at the metal scrap yard today picking through stuff to weld and on the way home the truck started seeming like it was skipping or missing on the timing or something. When I got home to back the truck into the driveway the truck died out on me. I quickly restarted the engine and noticed it was running rough. Seemed like the rough idle had begun to be more frequent of a problem. So I hurried and popped the hood and just watched and waited for it to start missing again. That's when I noticed that almost like clockwork, every 3 seconds, the A/C compressor would turn on and then off, then on then off, then on then off. You get the picture....

Does anyone know what would cause this? Is this a bad compressor? Bad compressor clutch? Bad regulator?

Your help, as always, is much appreciated!!

 

Its low on freon. Charge it up some and it should cycle like normal.

 

Could also be a bad low pressure cycling switch. Was the a/c blowing cold prior to this event?

 

What kind of freon do I need to buy? It's a 1996. Is something I can do or do I need to pay someone or have a license to buy it?

 

 

if its low on freon, you have a leak. Freon never needs replaced, and doesnt burn off like motor oil. So find and fix the leak first.

 

Well, the a/c seemed to blow cold when I am driving on the road but when I come to a stop at a stop sign or a stop light it gets warm again.

I went to the local auto parts store (O'Reilly) and the guy there checked my freon/refrigerant and the pressure was 55 psi. So, I guess I don't have a leak. He said there was no reason to add any more refrigerant and said he also thought it might be one of two things:

1. the switch on the compressor
2. the compressor itself locking up

HOWEVER, just as luck would have it, the problem would not reproduce itself while the truck was idling in park at the auto parts store.

Any suggestions?

 

Would the a/c relay going bad cause a problem like this?

Also, I have noticed before that when I switch the A/C on to "Max" in the truck sometimes the fan stops blowing altogether and I have to switch it back to "Normal" in order to get it to start up again. Would this have anything to do with it? Do the dash switches typically go bad?

Your help sure would be appreciated

 

That right there sounds like the low pressure cycling switch is bad. Your evap core is freezing over to the state of a solid block of ice, no air will blow thru that. (Yes it's a very common problem)

Without putting my hands on it to be sure, that would be a good cheap place to start. It's attached to the accumulator near the firewall.

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Stop taking advice from parts salesmen. They only sell parts. 55 is not right, and you need the high side pressure too to make an accurate diagnosis.