OK. You guys have helped me so much before. I am having an A/C issue on my 2007 King Ranch. It isn't cooling right. I have had the freon checked, the compressor checked and the snap-on computer hooked up to it and cleared all the A/C codes and in the shop it cooled to the point it was 50 coming out of the vents. Go about 1 mile and the same thing happens. it still is not right. Getting humid here and sometimes the inside windows fog up. My mechanic says he needs it for a few days to see what he can find. i asked him would it be wise if I disconnected the batteries and left them off overnight. He said that was a trick he uses sometimes and that it cannot hurt to try. Anybody got any ideas? 176,000 miles on the beauty.

 

Let's try the Super Duty forum for your year. Good luck with it!

 

 

Did you put the scanner on it while driving? Higher temps while driving from the radiator and intercooler could be causing the pressure switch to cycle while actually in operation. I think it's either ACCS or AP PID on the scanner.

X2 on a packed up orifice tube if the pressure is fine in the shop but spikes high enough on the road to cutoff the compressor. One of our '07s just had to get redone, it was originally an AZ truck with somewhat high engine hours to mileage, so probably idled for AC quite a bit.

 

Ah, the good old days when we only had to deal with the occasional low pressure switch failure.
Now, with my 2000 model SD the Powertrain Control Module controls most everything, including the AC clutch engagement. Not sure what the root cause of your failure is, whether it directly involves the PCM or an input to the PCM or if it directly related to the AC mechanics.
My PCM controls the positive and ground side of the factory clutch relay located at the battery junction box. The PCM twas providing the positive but for some unknown reason not the ground to engage clutch. So I just bought a cheap SPST switch, activated its coil via hot lead from series connected high and low pressure compressor switches, then used SPST relay contact to provide required ground to factory clutch relay. AC working super! Details at https://www.ford-trucks.com/forums/1...ac-clutch.html , though your wiring diagram details will most likely vary from my own.

 

Did anyone tell you what the high side of the A/C system was? Do you live/work in a dusty or dirty environment? The reason I ask is because the PO of my 06 F250 was a rancher running through the fields - the dust kicked up, plugged up the evaporator not allowing any flow through it. This skyrocketed the HI side of the system. The good thing is the evaporator isn't that bad to get to. Remove the passenger side fender well and the A/C case splits (unbolts) in half . Just a thought.

 

 

A good a/c tech should be able to get a handle on it pretty quick, just by watching the pressures while the system is running

 

Is the drain tube plugged? when you shut the truck off does it drip out of the bottom. If not than the drain is plugged and that's why the condensation is in the truck. Does the air coming out of the vents kind of smell? One more reason I think the tube is plugged.

 

Is your engine running hot by any chance? If the engine runs hot the computer turns off the AC compressor to eliminate it as a heat source.

 

OK. Dully noted. When I had the truck bulletproofed in June of '17, One of the things he added was a coolant filter system. It is dripping right now and he is going to replace that system when I get back into town and get the truck back to him. Does that change anything, or should I get the orifice tube replaced regardless. Not running hot. Had the transmission fluid and filters changed with Royal Purple and the truck runs really nice on the highway. 176,000 miles on it but the compressor is original as far as we can tell.Any other ideas? The insight has been as usual, incredible helpful.

 

 

With 176k on the clock you may start to get some debris on the orifice tube screen, but would not think it would be too serious unless compressor is wonky.. That screen is generously sized, about 2 1/2" long, can hold a pretty good bit of trash before it starts to have issues. Put a set of gauges on it, you will be able to see exactly what is going on with it. I probably would not change that orifice tube unless: 1) there was unusually high pressure drop across it or 2) was doing some other AC work. Tube comes out in about 10 minutes, just d-pressurize the system, pop the HP line open with a disconnect tool, grab orifice tube with needle nose pliers and pop in another (cost about 1 buck). Will need a new pair of o-rings (another buck). Pull vac on system for an hour and drop in 2-3 12oz cans of R-134.
In an older truck, that needs to have its freon topped off from time to time due to slow leakage, I like to throw in 1 oz of PAG 46 lube for good measure.

 

OK. Wanted to give y'all an update on the solution. Took the truck back to Hurricane Offroad in Mobile, AL., Owner's name is Brandon. He owed me an exchange on the coolant filter system to go to the Mishimoto system. Anyway, I told him about the A/C issue and he said that it sounded like to him that with the mileage the compressor might need to be shimmed. He said that when the unit gets hot, it stops engaging if the unit hasn't been shimmed. Didn't charge me a Dime and the wife and I went down to Dauphin Island for lunch and it will freeze your butt out of the truck if you have it on 60 degree max. Thought y'all might want to know. Thank you for all the suggestions.

 

Wow, some good news. And a super low-cost, quick fix that I would not have tried. Yes SD's A/C's are designed to really cool well!