Did some tests on the hvac pressure sensor today and when the signal reaches 3.5v or so the compressor turns off. I was using a test light with a digital voltmeter on it and when I connected with this the AC would come back on and run as it should until I disconnected. Repeated this several times to verify. Signal wire from transducer was reading 3.5v - 3.6v and Low Pressure was reading 60psi, I reduced to 55psi (3.0v) and now it is working like it should(not as cold at idle as I would like but at least the compressor is running and not blowing 100+ degree air through the vents. Will do more testing tomorrow and pull pressure/temp/voltage reading for this.

 

Work got busy haven't been able to more testing but looking around on the internet, Low side pressure should be 30-35psi. Is this correct?? I had reduced to 50psi before bringing back up to 55psi and at 50 psi it was not cooling. Pretty much ambient temp air coming out of the vent and the compressor engaged. If 35 psi is correct , would this mean my compressor is going out?

 

Also, why is the cooling fan a <pusher>?? This makes no sense to me. I argue that this only makes AC at idle more difficult. Any insight??

Are you saying the cooling fan is trying to push air forward through the rad/condenser?

 

That is correct. Fan spins counter-clockwise, looking forward from the drivers seat.

 

Yep. Not too happy with the Gene Messer Hyundai service center (Lubbock, TX) at all. Return appointment is for Friday and we will have a conversation about the 900 bucks I just spent and the trouble they didn't fix, that's for sure.

 

FIXED. So long story short, We did not take the car back to the dealer. The fan blowing in the wrong direction was the problem. Pulled connection loose to do some testing and the wires just came right out of the connector. Wired back up correctly and all is working. Seems that the fan blowing engine bay air through radiator and then the condenser caused the temp to get high enough to start tripping the pressure switch. Also found the ambient air temp and horn wire cut/broken possibly due to previous front end damage. Special thanks to Drunken Elvis for getting me to take a closer look at the fan direction.