2nd Gen Non-Engine/Transmission Air Conditioner Cut-Out?

[jschnacke]

Has anyone ever experienced this problem before? The air conditioner starts blowing hot outside air when idling. This has happend twice on the same day. Typical Indiana weather - 90 degrees with 80% humidity. Both times it was approximately 5 - 7 minutes after starting the truck and after a 1/2 mile drive. When getting up to speed, the air worked normally. It only happened at idle and standing still (waiting for my wife to get out of Wal-Mart). The truck will usually freeze you out while idling with the air on.



My dealer is going nuts trying to duplicate the problem, with no success.



Anyone else with this problem, or any suggestions for the dealer would be greatly appreciated.



Thanks,



John

 

[Powder Extreme]

John,



If for some reason your engine fan clutch is not engaging, you might not be pulling enough air through the air conditioner condenser. When the condenser gets too hot, the pressure in the system gets too high and it shuts off the compressor. It would act just the same as if you turned the control to plain vent. Gets hot in a hurry and seems to have high humidity making it feel worse.



Just a thought, I had it happen once in my '94.



Jerry



P. S. Welcome to the TDR!!!!!

 

[sam peterson]

The next time it happens lift the hood and see if the front hub of the compressor clutch is turning. If it isn't there may be to much gap between the hub & pully. ---Sam

 

[Joe Mc]

Once upon a time ago I was an HVAC Tech. and since my hobby is automobiles I always had chilly A/C.



1st thing - What Sam said,

2nd - (no specifics on your truck - no truck profile) assuming newer truck (as this is your first post and you are still dealing with the dealer) You may have a slightly restricted suction side strainer, which would trip the low suction switch. The low suction switch is a safety designed to protect/shut off the compresser clutch during a low refrigerant pressure situation. If it's OK at speed/other than idle the strainer may allow enough refrigerant to pass and cool the cab, then restrict again at idle. Sometimes things work their way into places they shouldn't on assembly lines during break times?

3rd - Check to see if your condenser coil is restricted - ton-o-bugs in the fins.

4th - Bad freeze stat (located on the evaporator coil in the heater box) This device is another safety, it's keeps coil from icing up and damaging the evap. It could be quick cycling on/off while at speed and you wouldn't notice.

5th and hopefully not your problem - Low refrigerant due to leak. On my truck (99) a line (located by the oil filter) to the compressor was rubbing against the turbo discharge pipe (to the intercooler) and wore away some of the aluminum pipe I adjusted things and protected this situation with a short length of split fuel line and pull ties.

6th - A wire is rubbing somewhere and interupting the clutch circuit. Only happens at idle due to increased engine wiggle which smooths out at speed.



I'm really stretching with that last one but, as you can see by now the possibilites are really unlimited. If your dealer can't figure it out you may want to try another one. Don't feel obligated to the dealer where you purchased your truck, be moreso obligated to all the hard work you are doing to pay for your truck and get it fixed right.



Let us know what they/you find. Happy trails and welcome to the TDR.

 

[WPeschel]

I am gonna goa ahead and pull this post out of the dump considering I am having this problem on my 98... Almost everytime I let it idle it blows ambient air... Also can someone describe what Sam means by the gap between the hub and pully... Thanks Wesley

 

[Joe Mc]

I am gonna goa ahead and pull this post out of the dump considering I am having this problem on my 98... Almost everytime I let it idle it blows ambient air... Also can someone describe what Sam means by the gap between the hub and pully... Thanks Wesley

I beleive what Sam is referring to is between the clutch hub and pully. If the gap is too wide then the cultch (even if it's working) may not be able to "grab" the compressor to turn it.



Now, can you explain what you mean by QUOTE: "I am gonna goa ahead and pull this post out of the dump". What is this supposed to mean????

 

[WPeschel]

I beleive what Sam is referring to is between the clutch hub and pully. If the gap is too wide then the cultch (even if it's working) may not be able to "grab" the compressor to turn it.



Now, can you explain what you mean by QUOTE: "I am gonna goa ahead and pull this post out of the dump". What is this supposed to mean????

What I mean by it is that it was posted 6 yrs ago... . Nothing negative about it... . I searched like every one should and pulled this one away from the dump... I guess I could have picked better words, but no disrespect I apologize. . Thanks Wesley

 

[RSICORP]

My 95 does the same thing. I have found my fan clutch to not be engaged. Fan spins slowly, no AC...After 450k on the original fan clutch I am thinking it is time to replace it. Once I get the rig moving, air is back to normal.

 

[RikDavis]

I had this happen on my 99 under two sets of circumstances.
The first is a collection of debri on the radiator. a circle of it the diameter of the fan could be seen looking down between the coolers and the radiator..
It would blow hot air at idle but be ok moving..

After the original fan clutch failed I replaced it with one from Advance Auto Parts. This clutch does not seem to engage when the truck is first started and will blow hot air. After the truck has been run at driving RPM for a few minutes it will be ok. The original clutch did not behave this way on start up