A/C question for the tahoe

[Old77]

my AC is not cold and I’m not sure why. It was cold until about 3 weeks ago and I’m not sure what’s happened. I’ve top off the r134a. That didn’t work. I replaced the climate control switch. That didn’t fix the air temp issue (needed replaced anyway). I have also replaced the actuator that controls the temperature. That didn’t fix it either.

Any other ideas? I’ve double checked the R134 pressure and it’s staying at the desired level so there’s not a big leak somewhere

 

[df2x4]

Is the compressor engaging? You should be able to see and hear the clutch on the pulley cycle.

 

[Old77]

Is the compressor engaging? You should be able to see and hear the clutch on the pulley cycle.

Yes

 

[east302]

Where do you live? Down here (Mississippi) it takes quite a while to cool down and it is still pretty lousy compared to the next generation trucks. It can only take the temperature down so much from ambient (maybe 30-40 degrees depending on humidity) so that can come into play.

Factory specs are below...

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That the blower is akin to a mouse fart does not help, try cleaning out the evaporator core if you haven’t already. Debris can restrict air flow and reduce temperature drop. Let us know if you need a how-to on cleaning that.

You said you replaced it, but is the temperature actuator adjusting correctly? It has a silver notched dial on it that rotates as the temperature dial is positioned. See if it changes position as the temperature dial on the panel is adjusted.

Also see if the heater water valve is closing when the temperature dial on the panel is set on the “max” setting. The valve is on the heater lines near the firewall. A plunger at the bottom moves to close the valve, shutting off coolant flow to the heater core to increase a/c performance. Feel the bottom of the valve, see if the plunger moves.






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[Old77]

Where do you live? Down here (Mississippi) it takes quite a while to cool down and it is still pretty lousy compared to the next generation trucks. It can only take the temperature down so much from ambient (maybe 30-40 degrees depending on humidity) so that can come into play.

Factory specs are below...

You must be registered for see images attach

That the blower is akin to a mouse fart does not help, try cleaning out the evaporator core if you haven’t already. Debris can restrict air flow and reduce temperature drop. Let us know if you need a how-to on cleaning that.

You said you replaced it, but is the temperature actuator adjusting correctly? It has a silver notched dial on it that rotates as the temperature dial is positioned. See if it changes position as the temperature dial on the panel is adjusted.

Also see if the heater water valve is closing when the temperature dial on the panel is set on the “max” setting. The valve is on the heater lines near the firewall. A plunger at the bottom moves to close the valve, shutting off coolant flow to the heater core to increase a/c performance. Feel the bottom of the valve, see if the plunger moves.






Sent from my iPhone using Tapatalk

Good list of next steps. I will take a look at these and see what I can uncover.

And I’m all too familiar with how the outside temps can limit how much the AC cools. I’ve had enough of these GMT400s to know their limistations this go around this isn’t the issue, unfortunately