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Waterloo · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

Going down the road, air blowing ice cold, have heater core valve off, ice cold and then warm air. I will get five minutes of ice cold air and then a half hour of warm air, and then back to five minutes of cold, and back, etc.

From what I can tell, is that the compressor is not getting the signal to turn on, and I'm thinking the thermistors or temp/high pressure switch? Any thoughts before I attack this new issue. I have the body controller switch installed, and that is not the issue. Fan in dash works, but have noticed that the Engine fan is not turning on when it normally would with the air on going down the road or just starting out from a stop. Need some help... Shaking head.

Dear Lord, just give me a week without issues!

Wiseman · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

I think your evaporator is building to much ice on the outside very quick and takes at least 30min to defrost and start working properly .
Or some moist wasn't evacuated from AC system after your overhaul and expansion valve is getting frozen on inside and don't allow freon vapors to go true evaporator . Pressure stay trapped between compressor and expansion valve until defrost and pressure drop down . Hi pressure switch is saying to computer : there's to much pressure and is shutting down compressor and fan all together. Is not AC compressor fault whit symptoms you describe.
Check the sleeper unit. If it's working while front one doesn't , then is ice buildup on front evaporator.
If shuts down both and comeback after 30 min. Is moisture in the system.
Did they replace the filter/dryer upon assembly? For how long they evacuated the system? Bottom line after staying open for such a long time is at least 1hr and new filter/dryer . Period!!!!!

stevesparts · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

Did you add any r134 to it?? sounds like to much 134 in it, overfilling will do what you are saying. and freeze up then blow hot air then cold,hot,ect,ect. sounds like you need to bleed off some r134. I did it one time and just had overfilled it as i thought just a little more would be better. but it wasn't. so check that out.
plus Wiseman tip about the dryer filter is a good one too :)

hhow55 · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

if it freezes up it has a restriction usually, expansion Valve ,the thing that is doing it ,but need to put some gages on it and see if the low side is going under vacuum since the low side in the suction side and it its vacuum ,but when the Guage's are hooked up on the high side and the low side ( suction & discharge ports) with the A/C on Max Fan on high the low side will stabilize at about 29.9 inches of mercery or 30 to32 inchecs of vacuum, if it starts going lower and the more rpm's added and the hight side climbs dangerously higher than 250 275 300 the high side line can and will explode, so if this is happening you definitely have a restriction, depending on what system r-12 or r-134-and this don't matters the type of vehicle does it have a orifice tube or expansantion valve they both do the same thing ,and usually this is what is wrong providing its full of freon and fan and all else is ok, this is most likely the place to look ok

RTRUCKING48 · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

(06-20-2016 )Waterloo Wrote: Going down the road, air blowing ice cold, have heater core valve off, ice cold and then warm air. I will get five minutes of ice cold air and then a half hour of warm air, and then back to five minutes of cold, and back, etc.

From what I can tell, is that the compressor is not getting the signal to turn on, and I'm thinking the thermistors or temp/high pressure switch? Any thoughts before I attack this new issue. I have the body controller switch installed, and that is not the issue. Fan in dash works, but have noticed that the Engine fan is not turning on when it normally would with the air on going down the road or just starting out from a stop. Need some help... Shaking head.

Dear Lord, just give me a week without issues!

I hear you Waterloo this prostars are no joke LoL,I have an issue similar to yours but on this truck the fan stays on all the time I check for leaks and nothing sometimes blows cold and at times hot, so I Think it's the high pressure switch went to dealer and damn!!!!! 181.00 for the damn switch,so what I notice when I turn the truck off and wait for 5 mins and turn it back on starts blowing cold air but the fan won't cut off stays on all the time so I need some help to before I break my piggy bank for the damn switch lol..

NewSon · 06-20-2016, **(Subject: AC issue... Compressor on its own schedule. )**

many answers and nice tips i found for me in these videos. hope it helps you

https://www.youtube.com/watch?v=MKGk05euwrw

Waterloo · 06-21-2016, **(Subject: AC issue... Compressor on its own schedule. )**

(06-20-2016 )RTRUCKING48 Wrote:
(06-20-2016 )Waterloo Wrote: Going down the road, air blowing ice cold, have heater core valve off, ice cold and then warm air. I will get five minutes of ice cold air and then a half hour of warm air, and then back to five minutes of cold, and back, etc.

From what I can tell, is that the compressor is not getting the signal to turn on, and I'm thinking the thermistors or temp/high pressure switch? Any thoughts before I attack this new issue. I have the body controller switch installed, and that is not the issue. Fan in dash works, but have noticed that the Engine fan is not turning on when it normally would with the air on going down the road or just starting out from a stop. Need some help... Shaking head.

Dear Lord, just give me a week without issues!
I hear you Waterloo this prostars are no joke LoL,I have an issue similar to yours but on this truck the fan stays on all the time I check for leaks and nothing sometimes blows cold and at times hot, so I Think it's the high pressure switch went to dealer and damn!!!!! 181.00 for the damn switch,so what I notice when I turn the truck off and wait for 5 mins and turn it back on starts blowing cold air but the fan won't cut off stays on all the time so I need some help to before I break my piggy bank for the damn switch lol..

Now that problem I have had, and it was the switch. It was replaced and all worked well...

I have rebuilt this AC system more times than I can count. Thousands of dollars in it. My thinking is like Wiseman stated, the expansion valve. I believe it is burned out, last one in here nearly melted, burned the crap out of it. The AC shop doing the work that finally got my AC system working after two years had never seen anything like it.

I'm running it into the dealer in a few hours. If they do not fix it, I am getting on Amazon and ordering the tools to do this work myself. I would go that route right now, but it is in the 90's here and am under a load so I just want this fixed asap. If not, I will have to run ACless until Sunday when I have time to work on it. Hotter than Hades here. And I would love to shoot the engineer at International that designed this POS AC system.

Waterloo · 06-21-2016, **(Subject: AC issue... Compressor on its own schedule. )**

Found the problem... The AC condenser in the firewall has a hole in it. New one coming in the morning. It never ends.

Wiseman · 06-21-2016, **(Subject: AC issue... Compressor on its own schedule. )**

(06-21-2016 )Waterloo Wrote: Found the problem... The AC condenser in the firewall has a hole in it. New one coming in the morning. It never ends.

Good lord!!!! Did you meant to say evaporator? This is what's behind the firewall.