NEED HELP AC not working. General question, please?

[GreenBravada]

Leaving for several days of camping with the little trailer. AC is not working.

Last year, it stopped worling and I cleaned up the mating surfaces of the clutch and it worked for about a year.

When it stopped this year, I immediately suspected the clutch and installed a new one $61 at Amazon. Seems well built.

Have everything back together now, and the clutch will not stay engaged. Is it the chicken or the egg?

I have a manifold set for checking AC, but I just put a can with a gauge on because it's late.

Pressure goes up to the top of the green, drops down to practically nothing and cycles back up. When it does this, the clutch engages repeatedly but only for a second or two.

The big silver can up by the coolant tank (dryer?) has some sort of sensor or solenoid. It clicks and the clutch engages. It clicks again and the clutch disengages. Cycles every couple of seconds repeatedly.

Please give me a jump start on this one because I have to leave about noon tomorrow.

Most likely the control system, the pressure sensors or the compressor?

I'm searching FAQs and prior discussions now.

 

[movietvet]

Sounds like low on refrigerant and the low pressure cycling switch is doing it's job. You have a leak, if the refrigerant is low. Most likely culprit is usually the shrader valves.

 

[GreenBravada]

Sounds like low on refrigerant and the low pressure cycling switch is doing it's job. You have a leak, if the refrigerant is low. Most likely culprit is usually the shrader valves.

I'm not sure how it could charge up above 20 psi and then just drop to nothing unless it is a MASSIVE leak. I do think that something is either turning the compressor off or turning the clutch off. Some kind of overpressure safety valve on the compressor?

I'm wondering if the AC control system is saying the proper temp has been reached and shutting things down.

 

[movietvet]

Your a/c system cycles. A properly filled system will engage the clutch and then disengage and then reengage. Watch a you tube video and see what I am trying to tell you.

 

[GreenBravada]

This YouTube shows exactly what I am experiencing. He replaced the pressure sensing switch and solved the problem on his truck. This might be my problem because it has always seemed as if it was a safety sensor that had gone flaky. Soooo....I guess that will be what I try to find in the morning.

Thanks for the input movietvet!

 

[budwich]

I have a manifold set for checking AC, but I just put a can with a gauge on because it's late.

why are you asking for the forum to "guess" what you can easily find out by using the equipment that you got?

 

[GreenBravada]

Because I am out of time and in need of some politely offered friendly advice. I explained that in my original post. Every automotive forum has a budwich.

(Once again, thanks for the input movietvet! Much appreciated and very helpful. Friendly, even.)

 

[movietvet]

Because I am out of time and in need of some politely offered friendly advice. I explained that in my original post. Every automotive forum has a budwich.

(Once again, thanks for the input movietvet! Much appreciated and very helpful. Friendly, even.)

If it had a MASSIVE leak, the refrigerant would be all gone and the clutch would not engage at all. If the cycling switch is bad, that is an electrical protection device that also has a shrader valve behind it. If the leak is small, then the system can still have SOME refrigerant in it. On a completely full system, there is a lot of pressure and if there is a small leak it will leak faster in the beginning but as the refrigerant leaks out, the pressure diminishes/drops and the leak will be slower and slower and can even get to the point where there is not enough pressure in the system to cause the system to empty. If you are looking for leaks, look for wet spots at junction points or at the shrader valve areas. The refrigerant oil in the system will leak out with the refrigerant and that wetness gets dirt in it and it will show. If open system, replace the accumulator and the cycling switch with quality parts and while open, flush the system. Do it all, ONE TIME.