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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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 Posted: Thu Jul 07, 2016 8:04 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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That will work, but use a 50 amp switch to match the fuse, my bad for giving the incorrect switch rating in my earlier post.
Also do consider using a 50 amp relay instead and triggering the relay through a switch off the "X" circuit. |
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fxr
Samba Member
Joined: December 07, 2014
Posts: 2325
Location: Bay area CA
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| Posted: Thu Jul 07, 2016 9:54 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| Wildthings wrote: |
| fxr wrote: |
You don't need a high current switch for my solution above ^^^.
And I was wrong - you only need an SPDT switch - a 2A capacity one will do fine:
[snip image] |
Except that when you have it in the manual high speed mode it will not kick the compressor off if the coolant temperature gets too high. |
Ah yes. 
This should work though:
_________________
Jim Crowther
1984 1.9l EJ22 Westy Wolfsburg Edition
Vespa GTS 300 |
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crazyvwvanman
Samba Member
Joined: January 28, 2008
Posts: 9937
Location: Orbiting San Diego
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| Posted: Thu Jul 07, 2016 10:16 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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Seems like a couple of diodes and a small switch would let you have a manual high mode and still keep rad switch mode as well rad temp switch safety control of compressor.
Mark |
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Wildthings
Samba Member
Joined: March 13, 2005
Posts: 50352
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| Posted: Thu Jul 07, 2016 10:45 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| crazyvwvanman wrote: |
Seems like a couple of diodes and a small switch would let you have a manual high mode and still keep rad switch mode as well rad temp switch safety control of compressor.
Mark |
Yes that would work as well. |
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dhaavers
Samba Member
Joined: March 19, 2010
Posts: 7757
Location: NE MN (tinyurl.com/dhaaverslocation)
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| Posted: Thu Jul 07, 2016 11:02 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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I smell a Jay Brown kit in the making...???
_________________
86 White Wolfsburg Westy Weekender
"The WonderVan"
<EDITED TO PROTECT INNOCENT PIXELS> |
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Snort
Samba Member
Joined: April 02, 2005
Posts: 1957
Location: Seattle, WA
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| Posted: Thu Jul 07, 2016 11:27 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| When this is happening, are you first seeing the medium fan speed come on before the high speed fan shuts things down? I haven't had much experience with this but my understanding is that the medium speed is only triggered by excess pressure in the high pressure side of the A/C, and I'm not sure how closely the outside air temp and the high pressure situation is related if at all. If the medium speed circuit isn't being triggered maybe you would be better off putting the switch there and leaving the high speed one alone. |
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Syncro Jael
Samba Member
Joined: December 19, 2013
Posts: 2204
Location: Utah
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| Posted: Thu Jul 07, 2016 12:57 pm Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| Snort wrote: |
| When this is happening, are you first seeing the medium fan speed come on before the high speed fan shuts things down? I haven't had much experience with this but my understanding is that the medium speed is only triggered by excess pressure in the high pressure side of the A/C, and I'm not sure how closely the outside air temp and the high pressure situation is related if at all. If the medium speed circuit isn't being triggered maybe you would be better off putting the switch there and leaving the high speed one alone. |
I am guessing my fan relay staging system is working correctly and that the medium speed has already kicked in. It is worth checking and should be relatively easy by jumping across the A/C Refrig. High Press. SW.
Still, my issue is that the engine is producing enough heat while slowly climbing grades with the A/C on that it will turn on the 3rd stage fan and disengage the A/C compressor. I have also seen the high speed fan come on without the A/C running on very long steep mountain grades in summer temperatures.
This modification should allow me to get a jump on the intense heat build up while traveling slowly and working the engine. It should be all about gaining some additional airflow across the condenser and radiator. Once the high speed fan does engage, the radiator will cool down dramatically, the fan goes into a slower speed, then the cycle begins all over again. If I can manually keep the high speed fan on while climbing steep grades, in hot ambient temps, it should easily overcome the on/off of the entire system.
I would also be interested to see if keeping the coolant temperature down will also keep my engine oil temps lower. I watch both temperature gauges and the coolant temps rise and fall quickly compared to the engine oil temps. The stock engine coolant temp gauge will be about centered in the LED when it is at 190°f operating temperature.
(I must note that the sensor for the coolant temp is monitoring the coolant leaving the thermostat inline to the radiator, the sensor is just before entering the radiator, HOT SIDE. With it in this location I can monitor the opening and closing of the thermostat)
I do appreciate all the thoughts and comments. It keeps me thinking... 
Top Gauge Pod: Voltmeter / Engine Oil Temp
Lower Pod: Engine Oil Pressure / Coolant Temp / Transaxle Gear Oil Temp
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat) |
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Syncro Jael
Samba Member
Joined: December 19, 2013
Posts: 2204
Location: Utah
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| Posted: Sun Jul 09, 2017 3:25 pm Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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I just wanted to update this thread.
I went ahead and installed a couple relays that are wired to the RAD COOL FAN THERMOSWITCHES. I installed an ON - OFF - ON switch at the dash. One side turns on the low fan = the other side turns on the HIGH fan. I then cut the BK/Y wire coming from the RAD COOL FAN RELAY and added a switch in that line. This lets me override the A/C COMPRESS CLUTCH and keep the compressor engaged when I turn on the HIGH SPEED FAN or I can switch it on and the system is back to failsafe mode of turning off the compressor if temps are too high.
So far this has worked flawlessly this summer. I am able to turn the high speed fan on early and it has no problems keeping the whole system cool. Even in 104º temps climbing canyon grades I have the A/C on and with the ability to turn on the HIGH SPEED FAN early, the system does not get hot enough to need the A/C compressor to ever turn off. I never need to run the fan very long so I watch the temp gauge often.
This is exactly what I was wanting. I do believe that once I get the new condenser installed this winter, the air flow through it and the radiator will be sufficient to keep things cool. My old condenser has been combed and cleaned, but I have a lot of fins that are just too bent to get a good airflow and I am sure there is still blocked passages after these many years of service.
I also love being able to turn on the low speed fan while off roading. It keeps the whole engine much cooler.
So far this has been a great modification for me and the EJ22.
Just FYI, and thank you again everyone for your comments.
Ron
_________________
1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat) |
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kourt
Samba Member
Joined: August 13, 2013
Posts: 1948
Location: Austin, TX
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| Posted: Sun Jul 09, 2017 8:08 pm Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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I'm about to embark on a similar modification.
The goal is to control all heat rejection systems manually. Another benefit to these switches is the ability to test the fan function. I just repaired the engine oil cooler fan due to stuck armature. With a manual override that would have been much easier to diagnose.
For the fan driven engine oil coooler, there will be a switch labeled AUTO/ON where auto is thermostatic control, on is manual control.
For the fan driven trans oil cooler, the same AUTO/ON idea.
Then three switches for three stages of fan, 1, 2, and 3. Auto or On.
Finally, the stage 2 (AC condenser) fan switch will also have an Off function.
Five fan control switches total.
Kourt
Last edited by kourt on Tue Jul 11, 2017 8:37 am; edited 1 time in total |
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JudoJeff
Samba Member
Joined: May 24, 2013
Posts: 1179
Location: Near Springfield, MA
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| Posted: Mon Jul 10, 2017 4:27 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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kourt,
Great idea, hope Jay Brown steals your ideas and markets a kit for us "dumb-asses".
Look forward to how you did this.
Jeff
_________________
________________________________________
1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout) |
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detoxed
Samba Member
Joined: May 10, 2014
Posts: 68
Location: S. Florida
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| Posted: Tue Jul 11, 2017 8:33 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| Ditto |
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Mac_Daddy_Westy
Samba Member
Joined: October 27, 2011
Posts: 154
Location: San Antonio, Tx
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| Posted: Sat Jul 29, 2017 1:58 pm Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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| Syncro Jael wrote: |
I just wanted to update this thread.
I went ahead and installed a couple relays that are wired to the RAD COOL FAN THERMOSWITCHES. I installed an ON - OFF - ON switch at the dash. One side turns on the low fan = the other side turns on the HIGH fan. I then cut the BK/Y wire coming from the RAD COOL FAN RELAY and added a switch in that line. This lets me override the A/C COMPRESS CLUTCH and keep the compressor engaged when I turn on the HIGH SPEED FAN or I can switch it on and the system is back to failsafe mode of turning off the compressor if temps are too high.
So far this has worked flawlessly this summer. I am able to turn the high speed fan on early and it has no problems keeping the whole system cool. Even in 104º temps climbing canyon grades I have the A/C on and with the ability to turn on the HIGH SPEED FAN early, the system does not get hot enough to need the A/C compressor to ever turn off. I never need to run the fan very long so I watch the temp gauge often.
This is exactly what I was wanting. I do believe that once I get the new condenser installed this winter, the air flow through it and the radiator will be sufficient to keep things cool. My old condenser has been combed and cleaned, but I have a lot of fins that are just too bent to get a good airflow and I am sure there is still blocked passages after these many years of service.
I also love being able to turn on the low speed fan while off roading. It keeps the whole engine much cooler.
So far this has been a great modification for me and the EJ22.
Just FYI, and thank you again everyone for your comments.
Ron |
---break--break---
Ron,
this sounds like a great mod, can you provide pics or a "how to" on this? I want to duplicate your process.
Andre |
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Mac_Daddy_Westy
Samba Member
Joined: October 27, 2011
Posts: 154
Location: San Antonio, Tx
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| Posted: Sun Oct 08, 2017 3:33 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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Hi Dave,
I like to mirror your A/C fan toggle switch, as quoted below. Would you be able to guide me through this? I drove from DC to TX, and will soon drive to CO and want to be able to switch the radiator fan on at command to cool the engine a bit.
thanks in advance, a detail set of instructions and pics if not too much trouble....please.
Andre
| djkeev wrote: |
Did it, I simply ran two wires to the A/C compressor area and fed the 12v through a dash switch.
I used an extra defrost switch mounted below the 4 Way switch, replaced the blank filler.
I got a roll of P-Touch tape, clear with white letters and labeled it.
My intent was to enable use of the Rear fans withoout the compressor running.
Dave |
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Ahwahnee
Samba Member
Joined: June 05, 2010
Posts: 9810
Location: Mt Lemmon, AZ
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| Posted: Sun Oct 08, 2017 7:48 am Post subject: Re: Manual Override Switch for A/C Compressor/Radiator Fan |
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If you use a SPDT switch such as a VW fog light switch you can select either a low speed or the high speed override for the radiator fan. Works with either the early 2-speed fan or the later 3-speed fan (you have to pick 2 speeds, I went with low & high).
Sorry, it has been so many years since I did this I would have to start all over figuring out exactly which wires I tapped into, but they are all right there behind the grilles.
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