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Big surprise, 2004 Avalanche AC system problem

71BBNOVA

New Member
Joined
Jun 3, 2016
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2
Hello, I have a 2004 Avalanche 1500 and am having some AC issues. First off its not cold enough, but the lines get ice cold, so I'm assuming I have an evaporator core/orifice tube issue. Sound about right? Already checked the freon on a machine, freon level and pressures are good.

Now the sort of common question, but with a little twist. What controls the blend door actuator? Mine has the typical cold passenger side, full heat driver side issue. But I just replaced the actuator with a brand new Delco unit, and also unhooked the battery and did the reset. The issue is that as soon as I turn the climate control system on, no matter what the temp setting is, the blend door actuator goes to full heat. I even took the actuator off and watched it when I changed temp settings. It goes full hot and won't go the other way. Is there a temp sensor it may need or a new control unit? Thoughts on this one? Thanks.
 
If pressure levels are correct for ambient temps... and not cold inside then my guess is a blend door is partially open to heat.
 
Actually, possibly related to this, when I got my '04 2 weeks ago, I noticed it was making kind of a "grunching" (grinding/crunching) noise. At first I thought it was one of the gauge motors since the speedo was shot, but I've since had all of them replaced. I've been running the AC, and it's blowing pretty cold, but I notice whenever I move the temp sliders, the noise gets worse. Thankfully, I live in SoCal, so I'll be using the air more than the heater, but makes me wonder if my blend doors and/or actuators might be on their last legs. Is this an expensive and/or difficult DIY fix?
 
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