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A/c not engaging

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Old 07-10-2012, 09:10 PM
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A/c not engaging

First off my a/c pump clutch would not cycle been like this for 2 years now just getting to it so I checked the gap 35 thous so I got it back to where it needs to be still no go blows air just no engaging of the clutch. Will it not engage if there is not enough freon in the system? Kinda lost trying to deal with this without taking it in. Never used a recharge kit so if that's what I need to do how do I go about it?
 
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Old 07-10-2012, 10:10 PM
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Yes, if the Freon is low or empty, it will not engage. There is a low pressure switch that you could stick a wire in as a jumper to see if it engages. Then just go get it charged and you should be good to go, unless you have a leak somewhere

Good Luck!
 
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Old 07-10-2012, 11:42 PM
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Where is the low pressure switch at on the pump? The truck has 184k on nothing has been touched as far as the a/c goes.
 
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Old 07-11-2012, 12:17 AM
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I believe it is on the high side hose... I think you unplug the connector that goes into it and then jumper the two connections inside. I will try to relay this post to a friend of mine tomorrow, he knows much more about the system than I do. I will see if he can post up and try to help you out a little more
 
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Old 07-11-2012, 12:26 AM
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I would appreciate it got a little one on the way and the wife is complaining about no a/c
 
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Old 07-11-2012, 07:42 AM
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The high pressure switch is on the high pressure line and the low pressure (clutch cycling) switch is on the accumulator-drier. The low pressure switch will open when the pressure is below 23 +/-1 psi. Remove the cap and quickly depress the schrader valve to see if there is still adequate pressure on the system. It could possibly be a bad switch. If so, you could temporarily jumper the low pressure switch plug to see if the clutch engages. If it does, check the temperature of the lines to and from the evaporator case for coolness. When fully charged, the upper and lower lines should be near the same temperature. If the upper line is less cold than the lower one, freon may need to be added.
 
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Old 07-11-2012, 07:50 AM
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Both lines were warm when I touched them when I was getting the clutch back into spec clutch never engaged but the lines were not cold at all. I will try to jump the switch and see what happens
 
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Old 07-11-2012, 08:08 AM
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Originally Posted by derek0525
Both lines were warm when I touched them when I was getting the clutch back into spec clutch never engaged but the lines were not cold at all. I will try to jump the switch and see what happens
Compressor must be engaged for lines to be cool. Check them after you get it to turn.
 
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Old 07-12-2012, 05:50 PM
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wiggle the wires on the high pressure line. if the clutch engages, replace the pigtail going into that switch. thats what i had to do
 
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Old 07-12-2012, 11:23 PM
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Originally Posted by PwerStroke99
wiggle the wires on the high pressure line. if the clutch engages, replace the pigtail going into that switch. thats what i had to do
Both pressure switches are in a series, so either one could cause an open circuit and keep the compressor from engaging.
Climate Control wiring.pdf
 
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Old 07-15-2012, 10:46 PM
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Gona look more into it tomorrow been Buisy this week I will let you guys know what I find.
 
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Old 07-19-2012, 07:51 PM
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Ok finally got around to checking things out and took some pictures So if I wiggle this harness the clutch will engage and the vent will blow cold air but I can't get it to stay engaged unless I pull up on it and it will stay on even breath on the harness it will go off. And this line was ice cold the one behind it was not very cold atleast not as cold as the front one. Hopefully the pics work
[IMG][/IMG]
[IMG][/IMG]
 
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Old 07-19-2012, 08:01 PM
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Looks like you need to replace the plug. Get the compressor running properly, then you may need to get the freon level checked with gauges. I'm not a big fan of the do-it-yourself cans you can get. I got a good education from a good friend of mine as to why those are not good.
 
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Old 07-20-2012, 02:37 AM
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What's the name of that harness I'm guessing I will have to go to the dealership to get it?
 
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Old 07-20-2012, 02:46 AM
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A/C Clutch harness would probably get you want you want.
I replaced my 01 shortly after the warranty expired.
Been fine ever since.
The larger suction line should be cold and sweating.
The other one will be warm to Hot.
Tom
 


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