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Hey! I’m new here and hoping someone can help! I have an 05 trailblazer EXT 4.2L 4x4. I’ve been having ac problems since I got it. At one point I swapped a fuse and it worked perfectly until the compressor gave out. For some reason at the time the fuse kept blowing. As of this week, I change the ac compressor, drier (accumulator), low pressure switch, orifise tube, relays and fuses, vacuumed the system and recharged it twice, and STILL ac is not working. When I first changed it, the compressor would kick on for about 15seconds and would shut off. It wouldn’t engage until the vehicle was restarted. So far I haven’t found any leaks, and I jumped the compressor straight to make sure it was working correctly and it was. I had jumped the connection to the pressure switch before I swapped it and it would engage, but now when I do it, nothing happens. The condenser looks okay, no bends or leaking fluid, but I’m assuming it may be clogged. When I swapped the orifise tube it was full of shredded metal. Is it possible that a clogged condenser would cause the clutch not to engage? Any help is much appreciated! Also quick side note, for some reason the rear air and passenger air comes colder faster, and the driver side would not come very cold at all prior to me swapping the compressor.
 

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2004 chevy trailblazer_lt
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2,581 Posts
Welcome to the Forum!

It sounds like there are a couple of different things going on here.

Question - do you have a manual HVAC system or an automatic HVAC system (numerical display where you dial in a temperature)?

First because of all the shredded metal you found on the orifice tube when you pulled the old one out, did you flush the AC hoses, and other parts with and AC flush to remove the metal pieces and other crap? If not, the system is still contaminated and you might have killed the new compressor you just installed. Also, since the condensers on these vehicles use micro channels through them in order to improve the heat transfer, there is no way to flush contaminates out of them, so you will need to replace the condenser.

When you added the refrigerant to the system, did you add refrigerant by weight or did you solely go by pressures (high side and low side)? Please tell me that you used a real set of AC gauges and not the hokey gauge found on the grossly overpriced cans of refrigerant found at all kinds of retail stores. If you did, great. So what are the current pressures? Is the big AC hose cold when the AC runs and does the much smaller metal hose warm to hot?

Second, when you turn the AC on, are you sure the compressor is getting 12 VDC?

Now for the requisite newcomer advisement:

DO NOT DISCONNECT THE BATTERY - REMOVE THE APPROPRIATE FUSE(S). Why? Because when you reconnect the battery, the HVAC actuators inside of the dash are commanded to run a recalibration procedure which stresses the old brittle plastic gears inside the actuators and the brittle plastic gears break and leaves you unable to control where the air comes out, or control the temperature of the air, etc. Replacing at least one of them literally requires the removal of the entire dash! So, if you ever need to actually disconnect the battery, such as in the case of needing to install a new battery, be sure and use some kind of Keep Memory Alive device to avoid the HVAC actuator recalibration routine.

Good Luck!
 

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'05 Chevy TB EXT
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Every EXT --- or other front/rear HVAC system vehicle --- required both of the RDs, expansion valves, evaporators and the condensor to be replaced before installing the new (not rebuilt) compressors or failure was 99% likely.

Ultimately --- at every class and clinic I attended on R134a, the final test of system charge - besides starting at the correct-by-weight recharge, was the overall temperature of the compressor as a good gauge to charge correctness.

About 160°F to 170°F was the best temperature.

If you can put your hand on the compressor and it's cool --- add more freon.​
If it's scorching hot and your skin sticks to it with a burning hair smell -- it's overcharged.​
Is it's uncomfortably hot, but doesn't cook your hand --- it's just about perfect.​

... and remember that the cans of R34a you buy are 12 ounces --- not 16 ounces, which is one pound equivalent!

"A pint's a pound, the world around!" is a good motto to remember.


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