Erratic A/C Controls, cooling
Thread Starter
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Mountain Pass
Joined: Jan 2013
Posts: 106
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Erratic A/C Controls, cooling
Two things going on now the heat in the Mid-Atlantic is finally here.
1) The Compressor is short-cycling at idle on initial startup. These trucks don't have a separate A/C fan so I am wondering if i've got a flaky high-limit switch. I've got a buddy with tools so this is less of a concern unless others can think something. FWIW - the A/C gets cold as soon as I put it in drive and start moving which points me towards the switch.
2) more puzzling - when I step on it, like accelerating up a hill, the airflow stops coming out of the dash and I think it's either hitting the floor or the defrost. When I lift off, it eventually comes back to dash air. Since I assume this system is vacuum controlled like most, that means that an increase in vacuum is causing the controls to react. Anyone ever experience this? Thoughts on where to start digging?
Thanks
1) The Compressor is short-cycling at idle on initial startup. These trucks don't have a separate A/C fan so I am wondering if i've got a flaky high-limit switch. I've got a buddy with tools so this is less of a concern unless others can think something. FWIW - the A/C gets cold as soon as I put it in drive and start moving which points me towards the switch.
2) more puzzling - when I step on it, like accelerating up a hill, the airflow stops coming out of the dash and I think it's either hitting the floor or the defrost. When I lift off, it eventually comes back to dash air. Since I assume this system is vacuum controlled like most, that means that an increase in vacuum is causing the controls to react. Anyone ever experience this? Thoughts on where to start digging?
Thanks
Postmaster
Joined: Aug 2005
Posts: 4,728
Likes: 8
From: Cleveland, TN
Two things going on now the heat in the Mid-Atlantic is finally here.
1) The Compressor is short-cycling at idle on initial startup. These trucks don't have a separate A/C fan so I am wondering if i've got a flaky high-limit switch. I've got a buddy with tools so this is less of a concern unless others can think something. FWIW - the A/C gets cold as soon as I put it in drive and start moving which points me towards the switch.
2) more puzzling - when I step on it, like accelerating up a hill, the airflow stops coming out of the dash and I think it's either hitting the floor or the defrost. When I lift off, it eventually comes back to dash air. Since I assume this system is vacuum controlled like most, that means that an increase in vacuum is causing the controls to react. Anyone ever experience this? Thoughts on where to start digging?
Thanks
1) The Compressor is short-cycling at idle on initial startup. These trucks don't have a separate A/C fan so I am wondering if i've got a flaky high-limit switch. I've got a buddy with tools so this is less of a concern unless others can think something. FWIW - the A/C gets cold as soon as I put it in drive and start moving which points me towards the switch.
2) more puzzling - when I step on it, like accelerating up a hill, the airflow stops coming out of the dash and I think it's either hitting the floor or the defrost. When I lift off, it eventually comes back to dash air. Since I assume this system is vacuum controlled like most, that means that an increase in vacuum is causing the controls to react. Anyone ever experience this? Thoughts on where to start digging?
Thanks
The part about the air shifting to the defrost outlets is low vacuum or a bad vacuum line, there is a VERY good chance it is a white one on top of the A/C box under the hood
Thread Starter
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Mountain Pass
Joined: Jan 2013
Posts: 106
Likes: 0
I'll also try putting in another can of freon. I have a spare 1lb can.
Thread Starter
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Mountain Pass
Joined: Jan 2013
Posts: 106
Likes: 0
Yes, will do because when the heat was down to around 80 deg last evening, it was working just fine. My friend has a full A/C toolset, going to have to stop by his place for a checkout.
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