A/C Compressor Question

[BigEd]

I have a '99 2500. It's 35 degrees out today and I noticed the A/C Compressor does not come on in any mode. Does it have an ambient temperature sensor or a low temperature cut out switch? I don't have the guages with me, but I can tell it does have some freon in it. Many thanks!

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'99 2500 4x4 Short Bed Quad Cab, Emerald Green, 5 Speed, Tonneau Cover, Bed Liner

 

[tlippy]

Ed - I have been wanting to ask a similar question.
I like the switch position that directs airflow to the floor and the upper vents - but I oftime don't want the A/C to operate. The owners manual states that "in this position, the A/C may be on. "
Question - What controls the A/C on/off in this position?

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99' Quad 4x4 A/T LB 3. 54 30K Miles.
26' Terry w/slide 7500GVWR
"KISS your truck and it will be forever faithful"

 

[B.G. Smith]

The Air Condition does not have ambient temp . cutout but the compressor will not operate in ambient of 30 deg. F or below because the low suction pressure clutch cycling switch opens at about 30 degrees F. bg

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White 99 3500, QC, 3:55, auto. most options except leather, Line-X bed liner, fiberglass running boards Rancho 9000s, bug shield and window vents, black vented 5th wheel tailgate, 100 gal. aux. fuel tank.

 

[illflem]

I know mine will come on in below zero temps after the truck is good and warmed up. I use a winter front so maybe the under hood temp gets high enough to close the suction pressure switch. I wish it wouldn't come on though,I finally had to modify the fan switch to keep it off in defrost.

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95' 25004X4,AT,Driftwood,Banks Stinger,Warn fender flairs and running boards(work truck)
95 3500,5 speed 3:54,BD E-brake,Driftwood,Banks&Psycotty,34,000 GCVW apple and tractor hauler(works harder truck)

 

[Eventer]

You want the A/C to run in colder weather because the A/C pulls moisture out of the air, such as from your breath. This keeps the inside windows from fogging up as badly.

OK, I didn't really know this. #ad
I heard it on Car Talk this morning! <g>

Feel free to correct me, but you'll have to answer to Click & Clack!


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Lyndon Hendry
Chief Equine Officer (CEO) and
President for Life
Head Over Heels Farm

2001 2500 QC LB ETH/DEE 3. 55RE Patriot Blue
Pop-Up Hitch, Stock engine except for MIA blow-by-bottle

"An oil burner for the hay burners. "

 

[illflem]

Lyndon,I understand the theory on how the AC helps defrost,and it works great,but when it's -15°,it sure isn't very comfortable. That's why I chose to modify mine like this

 

[Andy Perreault]

I have noticed on cold mornings when driving to work that sometimes the A/C would cut out and my windows would get fogged up. Now I know why! Thanks for posting this.
The A/C acts as a dehumidifier, that's why it's designed to run when you select the defrost position. If you run the A/C in any position (I use the recirculating position all the time), and turn the temperature knob to the hottest setting, you will get hot dry air (once the engine is warmed up). Disabling the A/C in the defrost position would ruin the dehumidifying effect! That would be taking a step backwards to the older pickup days where you couldn't get rid of the condensation even with the defroster on full blast.
When my A/C kicks out (and I have noticed the temperature reading is right around 30 degrees), I either turn the knob from the recirc position to the defrost position, or if I'm already defrosting, I turn the fan off and on again. For some reason, it seems to re-set itself and it starts working again, but only for a few minutes.
I agree with Illflem, I should try some sort of winter front to keep up the under hood temp and see if that makes a difference.
Andy