A/C Compressor Won't Cycle Off

[Stratosurfer]

All,
I have have hot-weather air conditoner gremlin type problems on my Tahoe. On a 100F low humidity day my side vents, (2 door tahoe, no rear A/C) is blowing down around 40F air. HOWEVER after about 20 or more minutes the coil ices up and the airflow begins to be considerably reduced. I have 'solved' the problem by pushing the A/C button to disengage the compressor for a couple of minutes as soon as the airflow begins to get slower. The ice melts, the flow picks up and then I again push the A/C button and repeat this procedure once about every 10 minutes.
Which switch is responsible for turning the compressor off when the air reaches a certain point? Is this a thermostat somewhere? Is this replaceable by the Layman?
Thanks

[Kick Ass Matt]

All,
I have have hot-weather air conditoner gremlin type problems on my Tahoe. On a 100F low humidity day my side vents, (2 door tahoe, no rear A/C) is blowing down around 40F air. HOWEVER after about 20 or more minutes the coil ices up and the airflow begins to be considerably reduced. I have 'solved' the problem by pushing the A/C button to disengage the compressor for a couple of minutes as soon as the airflow begins to get slower. The ice melts, the flow picks up and then I again push the A/C button and repeat this procedure once about every 10 minutes.
Which switch is responsible for turning the compressor off when the air reaches a certain point? Is this a thermostat somewhere? Is this replaceable by the Layman?
Thanks

Diesel Sub?

Front system I assume.

Didn't I mention to replace your O-tube in one of the other threads? If you havne't done so do it.

Replace your low pressure switch, located around the vacinity of your receiver dryer/accumulator.

Start with that...and then chances are your back is not working too...we'll worry about that later once you got it going...

Is it a shadetree job? no is not. You got to suck the system. Or do what I do w/some cars by venting the system on the LOW SIDE ONLY....yes I put it in caps for a reason...and its a reason that it's called the LOW side.

so yeah...vent the low side. Open her up, do what you got to do, button it up and go find someone w/a vac pump and charge you back up.

Whatever connection that you open up that has an O-ring? take the O-ring to a bearing house (industrial bearing supplier) and get it replaced. Hydraulic places would have O rings too. Just NBR (nitride black rubber) O rings would be good enough

and yeah, add oil.

Matt

[Robyn]

The low side pressure switch is located on the accumulator (large silver can by the firewall)

The pressure switch may be stuck in the closed position.

Try disconnecting the plug on this switch while the unit is operating, the compressor should stop.

The switch can be unscrewed from the schrader valve that it screws on to and a new switch installed without draining the system. 5 minute fix.

[Stratosurfer]

Try disconnecting the plug on this switch while the unit is operating, the compressor should stop.


Robyn,
I pulled the low side switch while running; compressor stopped. So much for the easy way out. I suppose I'll have to take her in to Mr. Goodwrench soon...
I am having fun running in 'manual' mode switching off the compressor with the A/C button when the coil freezes up and back on watching a temp gauge I've stuck in the vent. I feel like I'm back in the cockpit nursing home a semi-sick airplane on an hipshot work-around.