I have a 01 tahoe and the a/c is giving me problems. The a/c blows good when a lil chilly out side but when its real hot it stops blowing. The ac light on the dash will turn off and when you push it to turn on it just blinks and shuts off?

 

also already replaced the switch on the accumulator...could it be another switch anywhere.

 

Welcome to the forum...
When its cool outside the air coming into the vehicle will feel cool...
Do you have the rear AC?
When you turn the AC on is the AC clutch engaging on the compressor?
Is it cycling or staying on?

I suspect the system is low and needs a charge but most likely has a leak... I suspect the leak is at the rear AC components...

But answering some of the questions above will help identify that

 

yes i have rear a/c..the clutch does engage for a while then shuts off,but dosent cycle and ac light inside goes off. When you go to push the ac button to turn it back on it blinks 3 times then shuts off.

 

This is for the 07 but it may have some items that apply...


#07-01-38-003: Information for Vehicles with HVAC Control Module A/C and Recirculation Indicators Flashing


Subject: Information for Vehicles with HVAC Control Module A/C And Recirculation Indicators Flashing


Models: 2008 Buick Enclave

2007-2008 Cadillac Escalade Models

2006-2007 Chevrolet Monte Carlo

2006-2008 Chevrolet Impala

2007-2008 Chevrolet Avalanche, Equinox, Silverado, Suburban, Tahoe

2007-2008 GMC Acadia, Sierra, Yukon Models

2007-2008 Pontiac Torrent

2008 HUMMER H2

2007-2008 Saturn OUTLOOK

2008 Saturn VUE




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Condition/Concern
Some customers may comment that the Air Conditioning (A/C) indicator on the Heating Ventilation and Air Conditioning (HVAC) Control Module flashes then turns off after they press the A/C button. Others may comment that the Recirculation indicator on the HVAC Control Module flashes then turns off after they press the Recirculation button.

This is normal operation for the HVAC Control Module and indicates that the A/C or Recirculation function is not available at this time.

Reasons that the A/C may not be available (calibrated values vary by program) are listed below. Consult the appropriate vehicle Service Information (SI) for detailed HVAC Description and Operation:

• Ambient Air Temperature is too low (if equipped with Ambient Air Temperature Sensor)

• Vehicle voltage less than 9.5 volts

• Refrigerant Pressure too low

• Refrigerant Pressure too high

• Engine Coolant Temperature too high

• Engine is not in RUN

• HVAC Control Head is in the OFF position

Reasons Recirculation may not be available: Mode switch in Floor, Defog or Defrost mode.

The reason(s) A/C is currently disabled can be viewed with a Tech 2® by navigating to HVAC Data display and viewing the "A/C Permission" parameter.

Recommendation/Instructions
Do not replace the HVAC Control Module for a flashing A/C Indicator or flashing Recirculation Indicator, as this is normal operation.

 

do you know where that temp sensor is located..maybe that might be the problem?..thats the only thing i could think of..because it has 3 lbs of freon and that what it calls for.

 

its behind the grill right?

 

OK, 10 years old, I d say the seals on the hoses have deteriorated and your r134a leaks out. If the refrigerant level is low the AC wont cycle on nor stay on when it does. You can recharge with one can of r134a and see if the AC compressor clutch snaps on. I myself dont use r134a anymore. I found a better refrigerant, r12a. Environmentally sound, a larger molecule and it only requires 1/2 of the volume needed for r134a, which means the AC system can operate at lower pressure and it less likely to leak past the seals. It is totally miscible with older systems so no need for an evacuation nor discharge of the system.
Well just an idea, I charged these cars up last year and so far the system is still under pressure and it was cold inside the last time we had a hot day last month.

 

Yes, the exterior temp sensor is behind the grill but this should also provide the temp reading in your rear view mirror if you have that option...

 

silverado432: Welcome to the forum.

For sure you need to check the R134a charge level. It sounds like it's low and the low pressure switch is turning the compressor off.