Hey All, I have a 2010 Ford F-150 XLT 5.4L, 217,000+ miles. Manual HVAC Controls. I have been having some issues with the A/C compressor kicking on. Lately I will start the truck up and the compressor will blow cold air and cool, then down the road it will randomly stop. Sometimes I start the truck up and the compressor will not kick on blowing outside temp air, with the A/C on. But then I will drive for a bit and it will randomly kick and blow cold air.
I had a aftermarket compressor put in last year, and it worked fine. Previous one had a crack in the housing. I have had the truck in the shop and the refrigerator levels check and all is good there. He pointed me to an issue with the HVAC control module behind the dash and it not getting a signal to pcm then compressor. Another shop stated it was the compressor was bad when testing with his scan tool. I don’t think that’s the case, when it does cool it will cool for most of a drive. Recently I changed the HVAC control module( not knowing one off eBay has the be programmed) and then replace with old one after a/c compressor would kick on at all and the a/c kicked on immediately.

I am wondering could this be the issue, could it be electrical or could it be a bad a/c expansion value that as the system gets going it not prolly balancing the high and low side.
20 y/o college kid that likes to wrench, just looking for advice.

TIA

 

not super convenient but one of the times you start the truck up and the compressor doesnt kick on I would want to verify power to the compressor plug, if it doesnt have power then you can eliminate the compressor as the issue. If you dont have power the next thing Id do is go the hvac control and see if its sending the signal to activate the compressor and go from there. Probably need a couple wiring diagrams handy before hand and check also check them when the system is working correctly for verification.

if Forscan will show you the high side pressure like it does on my 12 that would help tell you if it's cutting out because the high side pressure is getting too high

 

I’d believe an aftermarket compressor is failing. Literally everything you can think of is made like 💩 these days. An electrical problem wouldn’t be hard for a competent shop to diagnose nor would compressor. Expansion valves in all types of refrigerant systems are far and away the most commonly misdiagnosed part.

 

Did some testing last night, have power at the A/C clutch plug, plugged back in and it didn’t kick the compressor. Rigged it up with pin tester into the back of the power connection at the a/c comp, with voltage tester from engine to cab to test voltage as I drove around. Had 13 entire time and a/c blew cold. (Of course I couldn’t get it to stop). Dielectric grease on connection and called it a night with it working. Come out this morning and no a/c on the way to work. I know I have power to compressor, at all times. I need to test voltage when it’s not working like you said.
It seems to occur after the truck has cooled and sat for some time, could a bad temp sensor lead to the pcm not kicking the compressor on, every time there is a fresh startup?

I am moving in the direction of a bad a/c clutch possibly

 

How did they check the refrig levels? Gauges only? I would have the shop connect to a machine that removes , evacuates and recharges correct amount.