AC not cooling

[2013megacab]

A few weeks ago I took the truck out and the AC wouldn't cool. After driving a few miles and perhaps turning on and off one or more times, it started working fine.

Yesterday it repeated the problem except it never recovered in 30-45 minutes of driving. When turning the AC on and off I do not hear the compressor start and there is no change in engine RPM. I looked for the compressor but it appears it is underneath stuff and only accessible from underneath. My code reader does not have the capability to test or report anything about the AC system.

Probably an unrelated symptom, but when I cranked the truck the outside temperature was displayed as 62 degrees when it was over 80. Over the course of 15-20 minutes it slowly came up to the proper temperature.

I do not hear any activity when changing from cool to heat and back. Is there a door that diverts air from the heater core to the evap, or does the air go through the evap all the time?

I am assuming either a refrigerant leak resulting in a low pressure cutoff, a clutch failure, or something in the control system.

Other than a fuse, is there anything I can easily check before finding an AC repair shop? We moved three years ago and I don't have a list of go-tos yet.

Thanks,

Al

 

[Diesel85]

Generally speaking low or high refrigerant would cause the compressor not to kick on.

Where are you situated at? Maybe someone has a shop suggestion.

 

[Tuesdak]

Inspection of the compressor clutch is the first thing you can do. Make sure it isn’t burnt from slipping as this will trip a one shot thermal fuse in the clutch coil.

on a cold engine start and turn on the A/C. Is the clutch spinning? Yes: check the two silver pipes for the evaporator at the firewall: they should be about the same temperature of COLD. If one pipe is not as cold or warm after about 2 min of running the A/C you have a low charge. If they are the same temp of cold and not cold out the vents, well on a cold engine, it should be cold. Cold engine so you don’t grab the heater pipes etc. and burn yourself! So if the A/C pipes are cold warm the engine up to see if the hot/cold door is stuck or broken.

 

[2013megacab]

Inspection of the compressor clutch is the first thing you can do. Make sure it isn’t burnt from slipping as this will trip a one shot thermal fuse in the clutch coil.

on a cold engine start and turn on the A/C. Is the clutch spinning? Yes: check the two silver pipes for the evaporator at the firewall: they should be about the same temperature of COLD. If one pipe is not as cold or warm after about 2 min of running the A/C you have a low charge. If they are the same temp of cold and not cold out the vents, well on a cold engine, it should be cold. Cold engine so you don’t grab the heater pipes etc. and burn yourself! So if the A/C pipes are cold warm the engine up to see if the hot/cold door is stuck or broken.

Thanks. I can't hear the compressor engage/disengage when turning the AC on and off. I will check to see if the clutch in spinning if I can get to it. I wasn't able to see it from above, but I will look again and try to get down to look underneath if necessary.

 

[2013megacab]

Generally speaking low or high refrigerant would cause the compressor not to kick on.

Where are you situated at? Maybe someone has a shop suggestion.

Thanks. I am in Fleming Island, FL which is south of Orange Park across the St. Johns River from Jacksonville.

 

[2013megacab]

Problem was a failed expansion valve.