AC help , freightliner cascadia

First step is determine WHY it shuts Down.
Is it high head pressures?
Does the engine fan cut in a lot on the highway when engine temp is low? At 60mph the ac shouldn't be asking for the fan much at all. If it is, head pressures are too high.
Is the high pressure switch cutting in?

Why was the first compressor replaced? Did it have an internal issue? If so, there is the possibility of compressor oil and shrapnel being forced out into the condensor.
If that's the case, did they FLUSH the system? If no, that's a problem.
If there is oil and shrapnel floating around it will clog the condensor, dryer and the expansion valve. These will create high head pressures making it shut down.
When the system is open,....ANYTIME.... the system is open, you replace the dryer and expansion valve. Did they do this?

A good flush, drain, measure and replenish the compressor oil. Vacume the system and refill with a new dryer and expansion valve.
If the compressor is bad they should be able to tell from their gauges.

 

Bet when they replace the compressor, they didn’t do a proper flush of the entire system.

 

This^^^^. Sounds like it’s overcharged. I doubt it is. Expansion valve is probably sticking, from debris or moisture. If moisture, you can turn it off, wait a couple minutes for the ice to melt inside the valve, turn it on and it will work till it freezes again. I’m not the A/C Guru by any means. I’ve been fixing my own 23 yrs now. After paying $600 twice in one month. Had a lot of practice replacing York’s every Yr. or 2 before learning the importance of flushing the system. Working without the proper tools. Shade tree guess work at best.

 

Any updates?

 

“Dryer wasn't replaced for sure ...”
It was mentioned that you prefer knowledgeable techs to work on your equipment. Anyone that has any basic understanding and workings of A/C systems and working on such things, knows you must always replace the dryer when a system is opened. Not throwing rocks but if this is a guy that’s regularly works on your stuff and did this…………..

 

Bot all good mechanics are good ac guys, found that out the hard way.
If he didn't change out at least the dryer when changing the compressor, hes not.
I'm NOT a good ac guy, but know a couple and have tried to learn as much as I can. And I still take my vehicles to them. Find a good ac guy. You will never get it right without that.

 

Cascadia does not have high and low pressure switches. There is a ####ty electronic device called pressure transducer . That junk sometimes screws the hvac module. Its not expensive. i would replace it first. If problem will exist than hvac module is malfunctioning.

 

First of all DL must be hooked up and hvac j1939 must be connected. there may be fault codes....