AC help
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AC help - 8/20/2008 6:44:58 PM
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Kage0113
Posts: 71
Joined: 5/30/2008
From: Laramie, WY
Status: offline
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Ok, let me start by apologizing in advance for A. This not being the right place to post and B. If this question was answered and I missed it. My AC wont work. Got a recharge kit and every time the compressor comes on, the pressure drops to the add part of the guage, but when the compressor turns off the pressure rises to the too much part of the guage. Not in the red, but the lower part of the yellow. It reads green, blue, yellow and red. What''s wrong with it? Any help appreciated. Again, apologies to Swart if the question was answered or if wrong section to post. But I spent an hour looking for an answer but couldn''t find one.
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1996 Chevy Blazer LT 4x4 4.3L V-6 Vortec Cold Air Intake, Hella 500 Driving Lamps, Mobil 1 Full Synthetic, SS Ultras, Alpine CDA 9847 CD Player
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RE: AC help - 8/20/2008 8:30:32 PM
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WolfPack
Posts: 2788
Joined: 10/30/2007
From: Raleigh, NC
Status: offline
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The pressure should get pretty high once the compressor turns off. You should always attempt the recharge with max a/c on and vehicle running. Then charge to the correct amount.
If that still doesn''t work, or you''ve already tried that...you''ve probably got a compressor issue..
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2000 Blazer 4d LS 4x4 - 265/70/15 General Grabber AT2s - Hunter Brush Guard - Surco Roof Rack with IPF 868s - 1.5'' Shackle + Tbar - 2'' BL
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RE: AC help - 8/20/2008 9:15:55 PM
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Kage0113
Posts: 71
Joined: 5/30/2008
From: Laramie, WY
Status: offline
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I had the Max A/C on and the vehicle was warm. I believe the pressure got to 60-65 PSI with compressor off and between 20-25 PSI with the compressor on. My friend said not to add any but I just wanted a second opinion. If I should add refrigerant, how will I know how much to add? Do i just wait for the compressor to turn on and add slowly till it gets to filled with the compressor on? Cause it seems that if I add refrigerant the guage will shoot up to the warning area when the compressor is off. The can says nothing about if to check when the compressor runs or if the compressor is off. My compressor comes on for about 3 seconds and then shuts off if that means anything but I assume it''s cause there is no refrigerant so it wont run long, at least that''s what it sounds like from other posts. The guage reads as follows: 0-25=low, 25-45=filled, 45-65= alert, 65+ is the warning area if that helps.
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1996 Chevy Blazer LT 4x4 4.3L V-6 Vortec Cold Air Intake, Hella 500 Driving Lamps, Mobil 1 Full Synthetic, SS Ultras, Alpine CDA 9847 CD Player
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RE: AC help - 8/21/2008 4:11:20 AM
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swartlkk
Posts: 14314
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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You can only use the reading on the gauge when the compressor is running. The low side pressure will equalize with the high side when the compressor is off. If you have trouble keeping the compressor engaged, you should supply power directly to the clutch to keep it engaged.
*Moving to 2nd Gen Tech*
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Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: AC help - 8/21/2008 6:20:09 AM
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Kage0113
Posts: 71
Joined: 5/30/2008
From: Laramie, WY
Status: offline
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Thanks Kyle. Thought it might be in the wrong place. How do I keep the compressor engaged? Do I need to get the RPM''s higher? Thanks again for your help. And it''s ok for the pressure to be high when the compressor is off? The pressure only matters when the compressor is on? Just double checking
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1996 Chevy Blazer LT 4x4 4.3L V-6 Vortec Cold Air Intake, Hella 500 Driving Lamps, Mobil 1 Full Synthetic, SS Ultras, Alpine CDA 9847 CD Player
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RE: AC help - 8/21/2008 6:26:46 AM
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swartlkk
Posts: 14314
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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The low side pressure is what matters and only when the compressor is running. Think of it as a pump, the suction of a pump will always be lower pressure than the discharge. In an A/C system, the compressor will not run properly unless the low side pressure stays high enough to keep the low pressure switch engaged.
You can force the compressor to stay on in a variety of ways. I use a set of jumper wires directly to the clutch as I find it to be the easiest way. You just need to determine which is the power wire and which is the ground (continuity test to ground on the vehicle side connector). Then run a ground and power wire to the battery.
Before they moved to these mini-relays, I just had a jumper wire to jump across the switched pins of the relay in the fuse box, but I don''t have any small spade connectors to make up a jumper for this anymore.
You can also jumper the low pressure switch to keep the compressor engaged. It is located on or near the accumulator/filter/dryer assembly that is on the passenger side of the engine compartment. Looks like a soda can, but about 3 times larger.
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Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: AC help - 8/21/2008 4:51:57 PM
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Kage0113
Posts: 71
Joined: 5/30/2008
From: Laramie, WY
Status: offline
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Here''s my update. I let the car run with the Max AC on as directed. I plugged in the r-134a and checked my charge. It was 15 PSI. The compressor went on for 2 seconds, then turned off, then on then off. I squeezed the trigger to let in the refrigerant while the compressor ran and I could tell it was taking it because the compressor started running longer, and longer. So all it was is it had low refrigerant. Got it to between 35 and 45 PSI. I couldn''t tell the exact pressure cause the guage isn''t the highest quality. So that''s that. Thanks for the help
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1996 Chevy Blazer LT 4x4 4.3L V-6 Vortec Cold Air Intake, Hella 500 Driving Lamps, Mobil 1 Full Synthetic, SS Ultras, Alpine CDA 9847 CD Player
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