2002 Avalanche a/c controls

[crhenkel]

So I have rebuilt and tricked out a 02 Avalanche for my daughter. It is all done and on the road. On of the things it came with was a warm ac system. I replaced a lot of it but kept the compressor. Vacuumed it down and it held soil filled it and it ran cold for a couple weeks. Now it is warm again. One of my main concerns is the control panel for the ac and heat acts weird a lot. I can likely find the leak and fix or seal it but I need help deciding if I should buy a new control unit or not. Any advice? It just doesn't seem like it responds to adjustment or fan settings correctly.

 

[Black02Silverado]

If it hasn't lost any freon, then it is the electronic controls. Some times the damper doors do not operate properly and so you get warm air instead of cold.

 

[ScottyBoy]

If it hasn't lost any freon, then it is the electronic controls. Some times the damper doors do not operate properly and so you get warm air instead of cold.

Yes, this statement is true. Both the control panel and the actuator have been known to fail. More often than not, the blend door actuator can fail and default to the hot setting. I had my control panel replaced twice while my truck was still under warranty. Was it the problem? Who knows, but it was the easiest thing to change so of course that's what the techs at the damn Chevy dealer replaced and claimed that it "should" fix the problem. I'll be perfectly honest, the blend door actuator in my truck has been intermittently sticking for at least 5-6 years now. I keep telling myself that I will replace it, but then as soon as it starts blowing cold again I hurry and unplug it. I will then leave it unplugged until Fall comes and the cooler weather arrives, until then I have NO need for any hot air to be blowing into my truck. Then come winter, I will leave it plugged in until the Spring time when it warms up then I just unplug it yet again. I guess if the day ever comes to where it sticks on hot PERMANENTLY, then I will be pretty much forced to replace it.

 

[crhenkel]

Good info. Thanks.

Thanks guys! I'll be checking the pressure on the system soon and then I will know the freon situation. The control panel is suspect. At times the actual fan speed does not match the knob position. Weird. And guidance on how to locate the blend door under the dash? I would like to check that too. Thank you in advance

 

[ScottyBoy]

Thanks guys! I'll be checking the pressure on the system soon and then I will know the freon situation. The control panel is suspect. At times the actual fan speed does not match the knob position. Weird. And guidance on how to locate the blend door under the dash? I would like to check that too. Thank you in advance

The blend door is pretty much behind the center console. To reach it, you need to remove the lower dash cover on the passenger side below the glove box. If you have ever replaced the cabin air filter, then you know the cover I am referring to, because this is the same cover that you remove to access the cabin air filter. The blend door actuator is actually to the left of the cabin air filter housing.

 

[crhenkel]

Which ac door actuator?

I was looking up the door actuator to order one. There is a temperature actuator a recirc one and a air distribution actuator. Are we talking about the door actuator for temperature?

 

[ScottyBoy]

I was looking up the door actuator to order one. There is a temperature actuator a recirc one and a air distribution actuator. Are we talking about the door actuator for temperature?

The temperature door actuator (also called the "blend door actuator") is the one that I was referring to. It's the one that switches the ducts from hot to cold. If it is closed to the hot side, the vents will blow hot air. If it closes to the cool side, then the vents will blow the cold air.
What EXACTLY is it doing? Is the AC just randomly going haywire and doing whatever it wants? Is it blowing warm air that just isn't cold, or is it actually hot air like the heater is blowing?

 

[crhenkel]

What it's doing is sometimes when the fan is turned off the blower still running on high other times when you tell it to turn air-conditioner on the air just lukewarm I did the whole replace parts vacuum it down it held for eight hours put all the Freon in oil back in like I was supposed to it was ice cold everything ran fine for about three weeks that it went lukewarm again so I'm guessing I probably lost Freon pressure so compressors not kicking on I need to check the wife and daughter are driving it right now she's practicing once I check the pressures I guess I'll know but I still think the controllers doing some very weird things

 

[crhenkel]

I haven't had a chance to do any checking on it yet the guy bought it from put enough UV Diane that system to choke a horse so I'm hoping there still enough left in it even though I did a pretty good flush that Ohta be able to see a leak somewhere if there is one with my UV light I didn't find any after I worked on it and it was right nice call but maybe there's one now small leaks are so hard to find

 

[ScottyBoy]

Yeah, if the fan is still running after shutting it off, that's sounds like the blower motor resistor or else the control panel may be bad. Usually if the resistor is bad, the fan will only blow on high and not on low or medium. But I did say "usually", so they don't always fail that way. I had one fail before that left the blower stuck blowing on high, even when you shut off the ignition! I had to disconnect it from the blower motor so it wouldn't kill the battery.
But if the resistor is bad, that doesn't have ANYTHING to do with it blowing lukewarm. Blowing warm is either the blend door acting up (which " could" be acting up because of a bad control panel) or else you have a refrigerant leak.
So if you have access to the AC gauges, I would check the refrigerant level. If it looks good, then I would go ahead and swap out the control panel.