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2003 gmc envoy_sle_xl
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Discussion Starter · #1 ·
Well I have been trying to diag this problem myself and I still have hot air blowing. 2003 Envoy XL 4.2L . The air con started blowing hot air. I have checked all fuses, both under seat and under hood. I have replaced the low pressure switch on the accumulator and I have check the charge...approx 35 at about 70 degrees outside air temp. The compressor clutch is NOT engaging. What can I look for next....or am I looking at replacing the compressor? Can I replace just the compressor if it is only the clutch gone bad? Any feedback would be greatly appreciated!!

Thanks
Tim
 

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2003 gmc envoy_sle_xl
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Discussion Starter · #3 ·
If i remember correctly the relay is in the under hood fuse box......and there were others with the same part number so I took AC's relay out(maybe #44-??) and put in another and still no engagement of the clutch. I do not know the high side pressure.
 

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2002 chevy trailblazer_lt_ext
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You would have to get a manifold gauge set and connect to both the high and low side of the A/C System. This would probably need to be done at an A/C Shop unless you can find a place that rents them.
 

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Discussion Starter · #5 ·
Thanks for the timely follow up. So at this point a professional "diag" is in order? Should that come back with "...compressor clutch is bad" can I get away with just replacing the compressor, assuming the compressor didn't tear itself up and leave little bits of itself through the system?

Again..thanks for the help...any other ideaas are greatly appreciated!!
 

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It depends on why the clutch failed. If the compressor seized, frying the clutch, then the entire system is contaminated and would need to be flushed. You would also need to replace the accumulator and orifice tube. If just the clutch went bad, then you would only need to replace the compressor, evacuate, and re-charge. You CAN replace just the clutch, but it is quite difficult to do, especially if you don't have the know-how or tools. Do you know if you are even getting 12V at the clutch with the engine running and the A/C on? If not, you could have bad low/high side switches, low refrigerant charge, refrigerant over-charge, shorted/cut/disconnected wiring, etc. In other words, if the clutch doesn't get 12VDC, it will not engage. Also make sure the ground is good. You could have good 12V, but a bad ground will not allow for enough current flow to engage the clutch.

A GREAT site for Automotive A/C repair can be found here:

http://www.polarbearinc.com/Trouble1.htm
 

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2003 gmc envoy_sle_xl
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Discussion Starter · #7 ·
I looked at wiring as best I could from underneath. I was thinking maybe wiring corrosion or damaged. I just had the left side bearing assembly replaced....do any of the AC wires get in the way of that repair? I did replace the low side switch to no avail. And my "pressure" reading is coming from a recharge can and gauge sold at Autozone.....maybe not the most accurate...lol.
 

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It is possible that the wiring could have been damaged or disconnected during that repair. Check around the area and underneath. The clutch electrical connector is on the front of the compressor between the compressor body and the clutch. The high side cut-out switch is on the back of the compressor.
 

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Discussion Starter · #11 ·
Well the 'Voy needed professional diag and I just spoke to the shop. The line to the rear ac unit has a leak from rubbing on the frame. The shop explained the repair would be a "release the body from frame" to replace the line or they could repair, and protect the line from rubbing, with high pressure hose. Still about $700 for complete diag and repair.....but something I was not going to be able to do myself.
 

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OUCH! At least it wasn't the compressor. When you get your 'Voy back, can you take some pictures of the repaired line and post? I'm curious as to their method of repairing the line.

At least you'll have working A/C again!
 

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2002 chevy trailblazer_ltz
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:m2:I thought I was going looking for this type of thread this morning, pulled the fuse & relay to check (while TB shut off) & clutch engaged when i tried again, phew...
 
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