2001 Tahoe 5.3L Intermittent Air Conditioning

[Panemic_Precision]

Greetings to all:

The air conditioning compressor in my 2001 Tahoe ceases operation and fails to cycle again after being stationary at a traffic signal or drive-thru, or when the RPMs or speed are low for a lengthy duration, such as during city driving. Until recently, deactivating it for around 5 to 10 minutes would resolve the problem. However, it has now ceased functioning and will not reactivate.

When the compressor cycles, the air is very cold, and the air conditioning functions as anticipated.

Conducted troubleshooting procedures:

Replaced the orifice tube, which was clean and devoid of dirt.
Replaced the radiator fan clutch.
Replaced Low Pressure Cycle Switch
Evacuated the system and maintained the vacuum for 30 minutes, then replenished the system to manufacturer specifications with R134a refrigerant.
Replaced the ambient air temperature sensor situated in front of the condenser.
Replaced the AC belt and tensioner; the belt seemed worn during the original examination, but this may not be relevant.
Utilized low-pressure water to externally clean the condenser fins.

The next suspect is the A/C clutch, which we will examine for voltage tonight. We have also replaced relays in the fuse box without any alteration. We have confirmed that the system remains charged and is not experiencing any leaks (used manifold gauges). The cycle pressures seem to be normal when the compressor is operational. It has been functioning sporadically but has now stopped entirely and will not power up at all. It is also noteworthy that when the low pressure switch connection is bypassed, the compressor fails to activate.

What are we overlooking in addition to the evident? The push switch will be addressed subsequent to the inspection of the AC clutch. Are there more sensors that may prevent the AC clutch from cycling?

To what degree may the head unit be held accountable for this? The AC indicator remains on when the compressor ceases to cycle. Is there a method to assess the head unit without removing it?

Seeking assistance urgently - all support is appreciated.

 

[Panemic_Precision]

REVISION:

I impulsively repositioned the A/C relay and the 10a AC fuse in the fuse box, then detached and rejoined the cycle switch connection. Subsequent to this action, the compressor activated for the first time in two days. It persisted throughout a stop at a drive-thru and thereafter ceased when navigating through the town. Nonetheless, it resumed operation after around two minutes. Remained for a few further minutes before departing once again.

I saw that the A/C relay was too hot to the touch when I removed it. Does it indicate a short circuit, or is that typical? I could hardly make contact with it.

 

[abracken]

Consider replacing the relay. They should not reach such high temperatures unless there is arcing at the relay connections or frequent opening and closure occurs. Notwithstanding that... I have not detected the relay functioning in my 2003 5.3L or 2006 4.8L vehicles. I will examine it during operation later today and inform you if the relay becomes too warm to the touch.

 

[Panemic_Precision]

Thank you for your response. I neglected to note that we updated the relays in the fuse box, but there was no alteration previous to the incident yesterday. The only action I undertook that we had not previously attempted was the removal and reinstallation of the 10a AC fuse, in addition to exchanging the relays. I will attempt a fresh relay next.

 

[ronemus]

If you exchanged relays, I am skeptical that a new one would resolve the problem. I will propose a few more items to verify.

Initially, if the coils are contaminated—particularly the evaporator coils located under the dashboard—or if the cabin air filter is excessively soiled, it might diminish performance and induce cycling of the compressor clutch owing to pressure accumulations. This may also occur if the condenser coils are contaminated.

If I neglect to replace the cabin air filter yearly in my wife's Subaru, she perceives a significant decline in air conditioning effectiveness, and the compressor operates with increased frequency of cycling on and off. Considering this, I examined my 1996 C1500 and 2006 Silverado, both of which lack a cabin air filter. I removed the blower motor and partly accessed the evaporator coils in the air handler behind the dashboard, discovering that the fins on the coils of the 1996 model were almost completely obstructed by dust and dirt. I applied coil cleaner into the aperture after removing the blower, allowed it to act for several minutes, and then used a garden hose nozzle to rinse the coils. The amount of contaminated water that flowed from the condensation drain on the firewall onto my driveway was astonishing. It significantly differentiated between a minimally functional air conditioning unit and one that emitted air at around 40 degrees.

Another potential problem is that although you replaced the expansion tube, any obstructions in the condenser might affect performance. It may be prudent to contemplate the replacement of the condenser (located in front of the radiator) and the accumulator (next to the firewall) if this has not yet been done. This would effectively remove all components except for the evaporator coil under the dashboard, which is difficult and time-consuming to repair, and the compressor, which is simple to replace.

Faulty pressure switches may also be a factor. I would observe it with high and low side gauges connected to see whether the pressures are elevated or diminished just before to the compressor's shutdown. I would begin with that examination.