A/C Problem

[budbowl7]

After using my Tahoe on our first day of hot weather for the year, I noticed that my A/C is not cold at all. I have owned the truck about 4 years and have never recharged the system or anything.

The compressor clutch runs for 1 second and then stays off for about 11 seconds. I hooked up a guage I have to it and the pressure builds to 45 psi when the clutch is not spinning and drops to about 10-15 psi when it does spin for that 1 second. The pressure then begins to build again when the clutch stops and it just cycles through this over and over. Can anyone offer me some advice? I don't now much about this A/C stuff and would prefer to do the work myself if possible.

[horse482]

It sounds like the charge is low, or it has a bad cycle switch/low pressure switch.

[MT-2500]

Originally Posted by budbowl7

After using my Tahoe on our first day of hot weather for the year, I noticed that my A/C is not cold at all. I have owned the truck about 4 years and have never recharged the system or anything.

The compressor clutch runs for 1 second and then stays off for about 11 seconds. I hooked up a guage I have to it and the pressure builds to 45 psi when the clutch is not spinning and drops to about 10-15 psi when it does spin for that 1 second. The pressure then begins to build again when the clutch stops and it just cycles through this over and over. Can anyone offer me some advice? I don't now much about this A/C stuff and would prefer to do the work myself if possible.

You are out of gas.
If he system has been that way very long you will need to pump it out and run a vacume pump on it to remove any moisture and check for leaks.
If it does not hold good vacume you have a leak. Look around for oily spots.
If no leaks recharge with the proper amount of freon and with a proper recharging gauge set that has high and low gauges both so you can watch both high and low pressure.
Also use the correct R-134-a freon and no stop leak crap or any blend freon that has them butane/propane mixers.
MT

[swp5767]

The 45psi reading, is that the high or low side. If thats the low side (which I suspect) what is the high side reading?

[MT-2500]

Originally Posted by swp5767

The 45psi reading, is that the high or low side. If thats the low side (which I suspect) what is the high side reading?

He said that was the pressure with compresser off and droped way down when compreser kicked in. Sounds like low side reading with low freon.
But as you say we need the high side reading to.
MT

[rumblefish73]

Hey guys, I have a 2001 Tahoe with rear A/C and i've searched the forums and I'm trying to find out what my low side pressure should be? My Tahoe won't cool at all at idle... The low side pressure is 60-75psi when the compressor is on and i it cycles off while sitting idle and goes up to 125-130psi... When traveling down the road today it was about 80 degrees outside and the front vent temperature was about 35 degrees measured with a decent clip-on a/c vent thermometer so I think it's doing a pretty good job. Sounds like some of you have low sides around 45 psi with no cooling so I'm guessing i'm ok but wonder if i could put in half a can to get it to cool better at idle?

[MT-2500]

Originally Posted by rumblefish73

Hey guys, I have a 2001 Tahoe with rear A/C and i've searched the forums and I'm trying to find out what my low side pressure should be? My Tahoe won't cool at all at idle... The low side pressure is 60-75psi when the compressor is on and i it cycles off while sitting idle and goes up to 125-130psi... When traveling down the road today it was about 80 degrees outside and the front vent temperature was about 35 degrees measured with a decent clip-on a/c vent thermometer so I think it's doing a pretty good job. Sounds like some of you have low sides around 45 psi with no cooling so I'm guessing i'm ok but wonder if i could put in half a can to get it to cool better at idle?

No. Do not ADD untill you get all pressure readings.
Get the low and high side readdings a idle and at 2000 rpm with compresser runnimg and post back all pressure readings.
Also read my upper post .
MT