Thread: Intermittent A/C

I hear you... But its better to fix it now before July & Aug when it will be very hot!! (with expensive $5 gas)..

Its a harness wiring problem and probably has a short somewhere in the new box..
Do you have some magic Electrical Grease? If so, put a dab on each relay prong and see if it works..

Sending a PM.. Call me

Checked the system and it is 65 lbs on the low pressure side when the A/C is off and around 35 psi when it is on (after tapping the relay.I am getting 13V to the power but Simon (Suckit) helped me out with checking the ground and when the A/C switch on the dash is on it is not getting any current. I think it may be a ground issue somewhere. I am going to swap dash switches as a start to see if that helps anything. How does the ground affect the relay? And where does it ground to. I am going to make some sense of the A/C diagram to see if there is something loose or missing.

We are beginning to think this is the case. Cause everything else is checking out good.

Your readings are low.. But its very strange that tapping the sensor will activate the AC...

COmpressor is probally not sending a signal to the relays. I am probally manually forcing it to open thus getting continuity.

FSM shows a different connection path.. Maybe you should test all you new connections for continuity.

The electronic signal comes from the fan & AC switch combo -> to the AC & Rad Fan relays -> to the compressor & Rad Fans.
With the dual cutoff switch monitoring line pressure.

So, if the dual switch senses low freon, it cuts power to the compressor to protect it. Tapping the relay should have no effect.

Or if the AC relay is bad or wire connection shorting out, the compressor will not come on (but the rad fans should come on full speed).
Tapping the relay may establish a connection.

Does your radiator fans stay on when the compressor is not on?
Or does the rad fans come on when you tap the relay?

Its the relay tapping thing that makes me believe that this is a electrical gremlin. AC system is a truly closed system with electrical controls. Other than that, the only external things is the mechanical clutch on the compressor and the rad fan activation.

Im stopping by the AC shop tonight on my way home. Ill ask him for things to check that we maybe overlooking.. They see alot more strange things than us..

The fans are off. The fans cuts in when the compressor turns on.

Stopped by the AC shop yesterday. His guess was low freon or bad dual switch.

He said to first check the high & low line pressures and make sure they are within spec on the AC label under the hood. Most of the time with he get cars with the intermitent ac thing, it caused by low freon pressure or a bad dual pressure switch. If its the dual switch, it will work intermittant for a while and then quit altogether. The dual pressure switch sits on top of the AC dryer. He recommended checking both.

You are correct. The high speed Rad fans are activated downstream of the AC relay.

I don't know where you're currently at with this, but in my wife's vehicle (Kia), My issues stem from either a faulty compressor, or a faulty dryer assembly. Reason I say faulty dryer assembly, is because when performing a charge with my A/C gauge set and a fresh bottle of freon, the system shows that it's low, yet will not allow me to charge it.

There's likely an issue with the dryer. When the A/C is running, it blows CRAZY cold, but then sometimes I get a face full of warmer/humid air, and you can smell the humidity.

My compressor is in fact falling off the deep end, too, though. If you start the car with the A/C on, the compressor makes a really loud knock once, but it doesn't do it all the time.

When I do check the freon level I will inform the forum. To be continued....