02 2.7 liter sebring AC works intermittently..165,xxx knocking on wood!!!
charge is good ...it'll squeal loudly somtimes when the
compressor is engaged and working...
then it somtimes just blow hot air won't work at all....
what parts are involved when it won't come on at all...
something is not letting the compressor come on at times..
the cooling fans are not coming on when the sytem is switched on and blowing hot!!!

 

"the cooling fans are not coming on when the sytem is switched on and blowing hot!!! "
Are you talking about the engine cooling fans at the radiator? They are independent of the air conditioner, and operate only when needed.

"it'll squeal loudly somtimes when the compressor is engaged and working..."
Squealing could be from a loose or worn drive belt; could also be from bad bearings in the A/C clutch.
"charge is good" Are you sure you haven't over-charged the system?

"what parts are involved when it won't come on at all..." The system won't come on if the body control module doesn't tell it to come on. The BCM , in turn, takes readings from various sources to determine if it should turn the A/C system on. Those include the settings on the control panel, the internal pressure of the system, the outside temperature, and the demand on the engine. If the pressure in the system is too low or too high, the BCM will not allow the system to come on.
There's an A/C clutch relay that takes a signal from the BCM and engages the clutch. That is a part that is involved in turning the system on.

 

If the system is over charged how would undo the over charge?
This maybe the problem.......

on most cars I have notice the engine cooling fans engage immeditatly
maybe a coensidense....just my general observevation...
The BODY CONTROL MODULE or computer...controls all... does make sense!!
I will change the belt As i'm sure it could use this anyway...
I do not believe it is the problem ....maybe only to fix the squealing

I guess I'm really asking is what parts control the switching, pressure checking, relays....and so on....and getting the over charge corrected so i can go through a trouble shooting list....
Logically thinking it works sometimes.......so I think theres an intermitten part failing?????

 

If you suspect an overcharge, there's only one way to fix it. You've got to suck out all the refrigerant and then put in a proper charge. There's no other way to measure how much fluid is in there. Best to have that done professionally, by someone with the proper equipment to evacuate the system without discharging the stuff into the air. In a perfect world they would give you credit for the stuff they take out because it can be re-used, but this is not a perfect world. The guy will apply a vacuum to the system for several minutes. This will have the advantage of drawing out any moisture that might be in there.

If you suspect that the pressure transducer is bad, it must be replaced. There is no adjustment or repair procedure for it. It's located on the discharge line near the condensor. If the pressure in the system is too high or too low, this device is supposed to sense that and open its switch, preventing compressor operation. It can be removed without discharging the system. To remove it, unplug the wire leading to it and screw it out with a 14mm wrench. Replace the O-ring with a proper A/C O-ring.

The compressor relay is located in the power distribution center in the engine compartment. There is a diagram under the cover describing the things in there.

One other possibility comes to mind. There's a temperature sensor on the evaporator core that shuts down the system if the core gets too cold. That prevents the condensate on the core from freezing and clogging up the air flow. You can access it through the glove box door opening. Disconnect the wire, then lift the locking tab and rotate the thing clockwise a quarter turn. Then you push it into the A/C housing and manipulate it out that way. Don't drop it into the A/C housing.

Good luck.

 

Thanks for the info....

Lastly is there any way to OHM out the parts in there static state to check if there bad before i just change them haphazardly?

Tempature switch or perssure transducer ??

Again thanks for the info.....

 

Both of those transducers are basically just off-on switches. Both must show continuity for the system to work. If either is open when it should be closed, then it might be bad, or it's working and showing a fault condition that needs to be addressed separately.
The relay is a standard part. Pretty easy to change out.