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Discussion Starter · #1 ·
I have read about the problems with this model not cooling very well and certainly mine is no different in the 5 years I have owned it. Took it to the dealer last year and they said it cooled down 20 deg below outside air and was ok(I'm sure they just cranked it in the shop). This is not my everyday truck. Recently I took the time on a trip to put a temp gauge in the vent. Outside temp was 88. At highway speed, inside truck was 79. Vent temp varied at norm to 75-76deg and on max after 5min to 72deg and after 10 min to 70 deg and stayed there. However, when stoping and truck going to idle the vent temp went down to 60 deg. Going back to highway speed, vent temp would go back to mid 70 again. Normally I think this scenario to be just the opposite,cooling only when driving fast. Does this give anyone a suggestion of my ac problem?
 

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Discussion Starter · #2 ·
My truck has the heater hose cut off that activates when in the max mode. I have also put a permanent cut off on the heater hose to see if it that would help and you can see from the temp differences of normal and max that it really made no difference.
 

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I just took a trip with a thermometer in my vent to show a GM owner what an a/c was supposed to feel like. My vent temps were between 50-55 depending on moving or idling at a traffic light. That was fan speed 2, normal a/c, ambient temp 98 degrees.

I would start with getting some pressure readings. Verify your entire cooling stack is clean. Check to see if the evaporator is clean. Your temp difference at idle could be an undercharged system that is excessively cycling with higher RPM. You could wire an LED light to the compressor pigtail so you could watch for when it cycles.

Another thing to check would be your blend door actuator.
 

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My truck started blowing north of 60* when the pump grenaded itself. Replaced the pump, lines, condenser, orifice tube, and drier. Last time I took a picture of the air temp, it was blowing 40* with outside air temp of 95* mid August.
 

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Discussion Starter · #5 ·
Summer heat has come so i took my truck to mechanic. He replaced both ac pipe lines coming to condenser radiator, the low pressure switch and electric connector, $545. At 92 deg, the cold air comes out at 59 deg now, 55 when on max air. :laugh2:
 
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