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Discussion Starter · #1 ·
I recently replaced my a/c compressor myself. It was purchased remanufactored btw. I drained and replaced the oil (7 ounces) replaced seals. After adding Freon it works great. Blows cold air but after driving several miles and shutting off the engine the compressor won’t “kick” on and blows only warm air. I tried bypassing the low pressure switch but nothing happened. I also noticed the dryer was very hot too. If I let the truck sit for a few hours the A/c usually kicks back on. After driving several miles again and shutting off engine the a/C compressor won’t kick on again. Anyone out there can help? Thanks
 

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2004 chevy trailblazer_lt
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Welcome to the Forum and your 1st post!

Year, make, model, engine, mileage and any and all DTCs please.

Now in the meantime:

It sounds like you could have a bad remanufactured compressor. However, we need to do some diagnostics first in case there is another problem. First, did you check the high side and low side pressures in case you have a leak? Second, you need to verify that voltage is getting to the compressor when the system does not work. When this happens, I would check to see that there is voltage on the appropriate pin of the AC Relay (Relay #44) in the underhood electrical center by placing a small gauge wire (like 20 - 22 gauge, twisted not solid) between the relay's terminal and the relay's socket. You should see battery voltage. Voltage seen - you have a bad AC compressor clutch - take it back, get your money back and see below.

Now for the important words of advice. Never purchase a remanufactured AC compressor regardless of brand or warranty. They are a part waiting to fail. If money is tight, then order a new compressor from rockauto.com as they will be considerably less money than a part store's remanufactured. (Even better is to order the AC Compressor kit which comes with the compressor, a new orifice tube, the accumulator, all the seals you need, and the compressor oil for about $30.00 more than just the compressor.)

To help you out, I've attached a schematic for the HVAC system.

Good Luck!
 

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'05 Chevy TB EXT
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Reman'd compressors are rebuilt with a paint brush --- I've taken a few remans apart and they have cut or sliced Teflon seals, metal in nooks and crannies, scored cylinders and pistons, sloppy swash plates - etc.
Pure junk.​

You COULD try to confirm 12V at the clutch though --- if it's there or not when the compressor is commanded ON.

Other than that ---> the compressor is the biggest loose canon here.
 

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Discussion Starter · #5 ·
I tried “jumping “ the low pressure switch on the accumulator. The engine will bog down like it’s under load but clutch won’t engage. I took the compressor off again and check the coil by jumping it with my battery. The clutch engages as it should. I replaced the high pressure switch located on the lines going to the compressor but does same thing.
 

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'05 Chevy TB EXT
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I tried “jumping “ the low pressure switch on the accumulator. The engine will bog down like it’s under load but clutch won’t engage. I took the compressor off again and check the coil by jumping it with my battery. The clutch engages as it should. I replaced the high pressure switch located on the lines going to the compressor but does same thing.
When the computer "sees" a load increase - which you created by jumping the low pressure switch, the engine should speed UP a little bit as it anticipates working with that new load.

Sumpthin's wrong here --- you did something incorrectly --- what I do not know --- but you got the wrong response.

You also shouldn't have had to remove the compressor to test the clutch. That was just odd on all levels.

I'm not sure you can be helped by me.
 
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