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djkeev
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Joined: September 30, 2007
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Location: Reading Pennsylvania
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DuncanS
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Location: New Hampshire
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 Posted: Thu Jul 22, 2021 5:07 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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| Do you want all the speeds? If so, the entire system needs to be energized unless you isolate the fan relays which would take some work. Another option would be to have a switch on the compressor relay to keep it from triggering. Interrupting the current path any where between current paths 20 and 26, shown on Bentley 97.144, including the ground would work. |
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crazyvwvanman
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| Posted: Thu Jul 22, 2021 5:45 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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Yes, by the diagram it would be very easy to do.
No need for a relay, just an added switch and a second power wire.
No need to cut or splice any stock A/C wires if you prefer not to.
All 4 fan speeds would work the same ways as in A/C mode.
No other part of the A/C need be live in fan only mode.
No time at the moment, back in a couple hours.
Mark
| djkeev wrote: |
I really like the air movement that the rear A/C fans create.
I want to install a switch where I can use these fans without the A/C compressor being engaged or the front radiator fan coming on.
I am thinking a simple on/off switch tapping into and feeding a strong fused 12v to the wire that feeds the fan switch from the A/C temperature (Snow flake) switch?
Wire it to an ignition source powering a relay. This way it only powers the fans with the ignition on.
Thoughts?
Suggestions?
Dave |
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DuncanS
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Location: New Hampshire
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| Posted: Thu Jul 22, 2021 6:45 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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As I said before, Mark is the man. I think what he my be proposing is a SPDT switch on the green/black 2.5 wire going between current path 4 and 9 on 97.143. The blower switch would receive power from either a new 15 ignition switch power wire to the SPDT, or the AC switch E35.
Now that I look at it, Mark, why is there a 2.5 wire coming out from a switch which is fed by a 1.5 wire? And how does power get to the thermostat K to feed the AC switch relay? |
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vanis13
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Joined: August 15, 2010
Posts: 3092
Location: ABQ NM USA.... Except when not
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| Posted: Thu Jul 22, 2021 7:25 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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seems like I can make mine do that just by turning my ac temp all the way to the warmest setting. If it still kicks kicks on for you at the warmest setting, how about just interrupting what ever signal the temp selector sends that kicks on the compressor - so the compressor is not kicked on no matter the temp? The rest of the system should just keep on working and the fan going at what ever speed you selected.
_________________
83.5 Westy with Subaru 2.5, 4 spd manual, center seat, COLD A/C on 134a!, Winter camp heated with an Espar B4 gasoline furnace
www.SuperVanagon.com - some stuff I make |
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djkeev
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Location: Reading Pennsylvania
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DuncanS
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Joined: October 17, 2013
Posts: 4583
Location: New Hampshire
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| Posted: Thu Jul 22, 2021 8:39 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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| The SPDT switch would do it without the radiator fan running. |
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crazyvwvanman
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Joined: January 28, 2008
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Location: Orbiting San Diego
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| Posted: Thu Jul 22, 2021 8:41 am Post subject: Re: "Hot Wire" A/C Blower Fan |
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While the A/C diagrams point to point wiring seems accurate there are some issues with wire sizes and colors not being exactly right.
If you look at the diagram on 97.140 it shows 2.5 wire in and out of the switch.
Yes, I'd put a SPDT switch in the wire from the thermostat/on-off switch to the fan speed selection switch. Then run another wire to the other leg of the switch, from either G1 or G3.
That way the fans would always be on the same fuse as before, plus only work when key-on but starter not cranking.
If you can find a switch with .250 male spades then you can remove the power-in wire from the fan speed switch socket and plug it into the new switch.
I think you already know this is a black wire though the diagrams show green/black.
Then a new wire with female ends, one end to center lead of switch and the other end into the socket hole you removed the stock wire from.
Finally, another new wire with female ends, from other leg of new switch to G1 or G3 on back of dash fuse/relay panel.
One thing to note with G1 and G3 is VW uses these for various options.
When an option is plugged into either of them, that option harness has an extra expansion pigtail on it so additional options can daisy chain to the same G1 or G3 fused power connection.
Mark
| DuncanS wrote: |
As I said before, Mark is the man. I think what he my be proposing is a SPDT switch on the green/black 2.5 wire going between current path 4 and 9 on 97.143. The blower switch would receive power from either a new 15 ignition switch power wire to the SPDT, or the AC switch E35.
Now that I look at it, Mark, why is there a 2.5 wire coming out from a switch which is fed by a 1.5 wire? And how does power get to the thermostat K to feed the AC switch relay? |
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djkeev
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Location: Reading Pennsylvania
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DuncanS
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Joined: October 17, 2013
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Location: New Hampshire
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| Posted: Thu Jul 22, 2021 1:46 pm Post subject: Re: "Hot Wire" A/C Blower Fan |
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I'm always reluctant to try and plug into any of the lettered pin connections on the back of the relay/fuse panel as there is such a jumble of wires, it's almost impossible to be able to see without causing stress on the wires back there. Thirty years old and all that..........
I will probably just tap into the black feed to the AC relay for my extra lead and keep the fuse. |
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djkeev
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djkeev
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DuncanS
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Location: New Hampshire
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| Posted: Thu Jul 22, 2021 7:03 pm Post subject: Re: "Hot Wire" A/C Blower Fan |
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| Huray!!! |
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djkeev
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djkeev
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