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tankyanker
Joined: 15 Dec 2007
Posts: 48
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| Posted: Mon Apr 07, 2008 3:33 pm Post subject: reducing fan 'on' time |
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| finally took the time to pull and rebuild my fan clutch. everything great, until i started running the ac again. when ac is on, fan cuts on all the time, throughout the temp. range, loaded, empty, etc. almost like having it locked in again. sucks mpgs, sucks power. anything i can do to reduce to amount of fan 'on' time while running the air conditioner? |
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allan5oh
Joined: 26 Aug 2005
Posts: 2233
Location: jackassville (winnipeg, mb)
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| Posted: Mon Apr 07, 2008 3:47 pm Post subject: |
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| No. The fan needs to be on while the compressor is running. |
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bob h
Joined: 15 Oct 2006
Posts: 670
Location: Nb
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| Posted: Mon Apr 07, 2008 4:23 pm Post subject: Re: reducing fan 'on' time |
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tankyanker wrote: finally took the time to pull and rebuild my fan clutch. everything great, until i started running the ac again. when ac is on, fan cuts on all the time, throughout the temp. range, loaded, empty, etc. almost like having it locked in again. sucks mpgs, sucks power. anything i can do to reduce to amount of fan 'on' time while running the air conditioner?
a/c high pressure switch?... is it unplugged? |
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tankyanker
Joined: 15 Dec 2007
Posts: 48
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| Posted: Tue Apr 08, 2008 2:38 pm Post subject: |
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| what is this switch, and where is it located? i looked at the compressor today, and all i saw were two coolant lines and then the electrical wire that feeds the clutch. i dont know what kind of compressor it is, it's old and dirty. maybe an alliance part. thank you mr bob. |
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tankyanker
Joined: 15 Dec 2007
Posts: 48
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| Posted: Thu Apr 10, 2008 7:58 pm Post subject: |
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| ac stopped working altogether, blowing but not getting cold. hi pressure switch is up on the dryer, on the firewall, present and plugged in. clutch on compressor not engaging. able to jump it or engage it manually from the pos. post on the battery. ? |
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allan5oh
Joined: 26 Aug 2005
Posts: 2233
Location: jackassville (winnipeg, mb)
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| Posted: Thu Apr 10, 2008 8:12 pm Post subject: |
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| Does your truck have an AC module? |
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tankyanker
Joined: 15 Dec 2007
Posts: 48
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| Posted: Thu Apr 10, 2008 8:33 pm Post subject: |
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| i dont know even know what an a/c module is allan. i'm scraping together an ac repair education off the internet right now, lol. i was going to check the breakers tomorrow, but i guess i was wondering ... what happens when you slide the switch on the dash, i know that part is air actuated, at point or where, or how does this air action become an electrical signal. because i'm losing the 'fire' somewhere between the dash and the firewall. |
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pdm
Joined: 11 Feb 2008
Posts: 60
Location: Waterloo,Ontario, Canada
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| Posted: Thu Apr 10, 2008 8:51 pm Post subject: |
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You can try jumping the low & high pressure switches, also depress the schrader in the access port (careful though, it may have pressure there) If there's no pressure the system has a leak & the compressor won't run.
What make, model year of truck is it? & did it affect the way the fan clutch worked when the a/c quit? |
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allan5oh
Joined: 26 Aug 2005
Posts: 2233
Location: jackassville (winnipeg, mb)
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| Posted: Thu Apr 10, 2008 9:04 pm Post subject: |
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| Do NOT bypass anything. What year is the truck? |
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solo379
Joined: 14 Feb 2004
Posts: 3163
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| Posted: Thu Apr 10, 2008 9:32 pm Post subject: |
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allan5oh wrote: No. The fan needs to be on while the compressor is running.
On my old 96 Volvo, it was on/off with AC on. On this one, it's only on/off, when I'm sitting still when I'm running it's only comes on with the temperature. AC is working fine. |
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allan5oh
Joined: 26 Aug 2005
Posts: 2233
Location: jackassville (winnipeg, mb)
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| Posted: Thu Apr 10, 2008 9:46 pm Post subject: |
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| Yes, but the compressor isn't running all of the time. Maybe 20% of the time. When the compressor turns on, the engine fan kicks in. |
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solo379
Joined: 14 Feb 2004
Posts: 3163
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| Posted: Fri Apr 11, 2008 7:37 am Post subject: |
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| No Allan, not even once! I even thought that something wrong with AC at first! :shock: :D |
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TK THE TRUCKER
Joined: 11 Jul 2004
Posts: 894
Location: NEAR ROCHESTER, NY
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| Posted: Fri Apr 11, 2008 8:11 am Post subject: |
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| I've had this happen with one of our fire trucks. I took it to have a service done and also the ac charged. It was hot out that day and on the way back I had the ac on and after a while I noticed the fan was running non stop which it had never done before. I took it back and they said that they over charged it so when the system warmed up to normal it was showing high pressure in the lines which tells it that the system was overheating thus causing the fan to run all the time. They recharged the system with the proper pressure and it has been fine ever since. 8) 8) |
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tankyanker
Joined: 15 Dec 2007
Posts: 48
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| Posted: Sun Apr 13, 2008 1:33 pm Post subject: |
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| replaced a 'micro-switch' in the dash, a little black bugger behind the ac control panel that has a 'clicker' and two prongs. now, 95% sure that fire is being sent from the panel to ... the breaker? all the breakers are old and have no labels. looking for a breaker diagram online. ac clutch still not engaging. sending fire from panel ... to wherever ... but no fire is coming out of the firewall into the ac dryer where the hi-pressure switch plugs in. |
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pdm
Joined: 11 Feb 2008
Posts: 60
Location: Waterloo,Ontario, Canada
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| Posted: Sun Apr 13, 2008 8:48 pm Post subject: |
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In your previous post you mentioned powering the clutch directly......if you do that for a few seconds does the small line get hotter & the big line get colder?.....if not you've lost the freon in the system.
The a/c only needs the fan on when there is low air flow over the condenser. At road speeds the fan doesn't need to run for the a/c to work. It operates independent of the compressor clutch. |
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