12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

A/C Only works at Idle

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Old 06-13-2014, 10:16 PM
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Default A/C Only works at Idle

I have been doing some searching and can't find a solution to my problem. When the truck is in park idling and the truck has warmed up the A/C works great, but as soon as I move it/increase the RPM's it just blows the same amount of heat no matter what temperature setting is selected. All of my position selections work also. Any help would be appreciated.
 
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Old 06-14-2014, 10:11 PM
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I havent been into one of these.. have you had guages hooked up yet ? what were the pressure's when it was running ?
 
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Old 06-15-2014, 05:59 AM
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Sounds like the clutch on the condenser is slipping. Not saying that's it, but I had the exact same thing happen with a 5.0 Mustang. Changed the clutch, wasn't the issue. Turned out to be a bad wiring harness.
 
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Old 06-15-2014, 09:18 AM
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Thats why I asked about pressure's .. if there's no pressure its either the clutch or he has a leak and there's not enough pressure in system to activate the low pressure switch to enguage the A/C clutch ...
 
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Old 06-17-2014, 08:33 PM
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I have not checked the pressure yet. I will when I can get home in a couple days. Thanks for the help.
 
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Old 06-17-2014, 11:26 PM
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yeah, Im thinkin thet the orfice tube or expansion valve is clogged .. your statement about it will work @ idle and the when you giv e the engine RPM's it goes off, makes me think the high pressure switch is cutting out the clutch due to high pressure, or could be low on charge , if you can , get some guages whe you get back and post what you find out, will check back when ya post again ..

Keep us posted...
 
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Old 06-23-2014, 09:16 PM
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Did you recently "top off" the refrigerant? It could be possible that the head pressure is too high and the high pressure cut off switch is opening. Or by the same could be the low pressure clutch cycle switch acting up. Let's see what happens after gauges are hooked to it. Harbor freight has some on sale for 54 bucks, and they work very well.
 
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