Automotive Air Conditioning Information Forum (Archives)

seijirou on Sat September 05, 2015 1:48 PM

Year: 2005
Make: Ford
Model: F350
Engine Size: 6.0L
Refrigerant Type: r134a
Ambient Temp: 90F
Pressure Low: 23-58
Pressure High: 155-200
Country of Origin: United States

My AC isn't performing very well and is generally behaving strangely.

After sitting a while it will come on and blow "cool" air, but not really cold air. I still need to find a thermometer to get the actual temperature.

Sometimes after running a while it will just stop working. The compressor will no longer come on.

Otherwise it cycles very often. I finally got some gauges and I can see why it's cycling now, the low pressure is fluxuating a lot and I'm pretty sure it's the low pressure cutoff switch doing its job.

Here is a link to a video I took of the cycling and the pressures.

https://goo.gl/photos/nQfZteJRDCmpfAhV9

mk378 on Sat September 05, 2015 8:25 PM

It seems undercharged. Always start a diagnosis with the proper charge by weight. If the charge is low, look for leaks.

The compressor should come back on around 50 low side. If it is going much past that, or not coming on at all sometimes, the switch is likely bad.