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0to60in6min
Samba Member
Joined: November 27, 2006
Posts: 3460
Location: OR & CA (Oregon/California)
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 Posted: Mon Sep 14, 2009 4:51 pm Post subject: manual switch for fan radiator |
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hi all,
I would like to put an emergency/over ride switch to turn on manually the radiator fan (just in case the temp sensor fails). I need some instruction for the wiring... help anyone?
(89' vanagon)
thanks in advance |
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markmc90
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Joined: June 13, 2007
Posts: 295
Location: Portland, OR
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| Posted: Mon Sep 14, 2009 4:57 pm Post subject: |
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I too would like to do this. I've only had the fan come on a few times but it seems too late. I think you could keep your temp down by activating it at a cooler temp. Someone must have already done this.
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87 Syncro |
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whafalia
Samba Member
Joined: January 28, 2009
Posts: 685
Location: San Francisco
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| Posted: Mon Sep 14, 2009 4:58 pm Post subject: |
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| Yes, and notes for an 85 too please, if different, this happened to me Friday while in line at the Mexicali border crossing, got extra questioning as I was a little sweaty and jumpy after pushing for a few hundred yards. Now have a manual switch but would like to be back on auto with the option to kick it in. |
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syncrodoka
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Joined: December 27, 2005
Posts: 12397
Location: Santa Cruz, CA
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| Posted: Mon Sep 14, 2009 5:07 pm Post subject: |
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| It should be super simple to do- tap into the two wires that go to the temp switch in the radiator and tie them into a on/off switch. One position it will act like normal and the other position it will manually override and turn on the fan. Good luck. |
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whafalia
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Joined: January 28, 2009
Posts: 685
Location: San Francisco
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| Posted: Mon Sep 14, 2009 6:41 pm Post subject: |
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| I'm just not a fan of those taps even though I've used them many times and rarely had a problem, but yeh simple as that, thanks. |
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syncrodoka
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Joined: December 27, 2005
Posts: 12397
Location: Santa Cruz, CA
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| Posted: Mon Sep 14, 2009 6:46 pm Post subject: |
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Are talking about these taps? http://www.crowbarelectricalparts.com/Scotchloks.htm
I was just talking about making a piggyback connection- I should have been more clear. I only solder and shrinkwrap wire connections if at all possible. I never use those wire taps.
I forget that there are actually 3 wires there. You can jump them with a piece of wire to figure out which will turn on the low speed fan. one combination will turn on the low speed fan, another combination will turn on the high speed fan and the last combination won't do anything. Tap into the two that turn on the low speed fan. Good luck. |
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aquaboxa
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Joined: August 30, 2009
Posts: 96
Location: Upstate NY
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| Posted: Mon Sep 14, 2009 7:02 pm Post subject: |
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It would have to default to the temp sensor in the off position.
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'89 Vanagon Bluestar
a.k.a. "The Bermuda Rectangle" |
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wcdennis
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Joined: July 20, 2004
Posts: 955
Location: Winston-Salem NC
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aquaboxa
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Joined: August 30, 2009
Posts: 96
Location: Upstate NY
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| Posted: Mon Sep 14, 2009 7:20 pm Post subject: |
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dang it! we wanted to rig somethin' up!
No, no. GREAT find - I'll be ordering one ASAP!!
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'89 Vanagon Bluestar
a.k.a. "The Bermuda Rectangle" |
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thewump
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Joined: June 15, 2008
Posts: 215
Location: Denver
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| Posted: Mon Sep 14, 2009 7:29 pm Post subject: |
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| syncrodoka wrote: |
| It should be super simple to do- tap into the two wires that go to the temp switch in the radiator and tie them into a on/off switch. One position it will act like normal and the other position it will manually override and turn on the fan. Good luck. |
No need for a relay?
K
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syncrodoka
Samba Member
Joined: December 27, 2005
Posts: 12397
Location: Santa Cruz, CA
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| Posted: Mon Sep 14, 2009 7:49 pm Post subject: |
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| You are only dealing with grounds not power- no relay needed. I have driven over 3 hrs. with a wire jumping the low speed fan when the original fan switch failed without any problems. |
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whafalia
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Joined: January 28, 2009
Posts: 685
Location: San Francisco
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| Posted: Mon Sep 14, 2009 8:02 pm Post subject: |
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| 3 hours with a cotter pin here. |
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syncrodoka
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Joined: December 27, 2005
Posts: 12397
Location: Santa Cruz, CA
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| Posted: Mon Sep 14, 2009 8:09 pm Post subject: |
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| Well I went out and checked it with a volt meter and it does have power at one of the outside connectors. A look at how it actually functions and relay would probably be best. I thought that it was a heat operated 2 stage ON switch, but it is a little more. I would downgrade it from super simple to easy. |
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10151
Location: Abiquiu, NM, USA
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| Posted: Tue Sep 15, 2009 10:05 am Post subject: |
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| syncrodoka wrote: |
| Well I went out and checked it with a volt meter and it does have power at one of the outside connectors. A look at how it actually functions and relay would probably be best. I thought that it was a heat operated 2 stage ON switch, but it is a little more. I would downgrade it from super simple to easy. |
The fan switching is done on the hot side, but even if it were switched on the grounded side, you'd still have to make a circuit that can handle the amps. Electrics 101: current is exactly the same at every point in a circuit. There's no voltage on the grounded side, but just as much current, all the way to ground.
So if you were to switch the wires that feed the temp switch directly, you would need to size your added circuit to handle the fan's current. That could be a lot depending on which fan speed you want to run. A relay would definitely be favorable to running fat wires all the way back to a switch on the dash, plus the switch would have to be big enough as well, which means it is larger and more expensive.
I installed one of the low-temp radiator switches recently in a customer's Syncro, at their request. It came on so much of the time I actually found it pretty annoying. There honestly is no need for that much extra cooling under normal conditions, your taste or your paranoia may tell you different, some people believe that more cooling is always better, but I don't subscribe to that thinking. If it's a band-aid for inadequate cooling, the attention should be on making the system work as-built, which probably means a new radiator if you've serviced everything else.
I do, however, like to have proactive cooling for low-speed dirt-tracking, which I have to do just to get to my house, besides our weekend trips. Climbing steep rugged forest roads in the mountains involves long stretches in low gear with higher rpms and little road-speed, which heats up the oil a lot and keeping the cooling system at a more consistent temp helps there. This is a special condition and doesn't relate to day-to-day on-road driving where the stock system is more than adequate.
I'm only going to talk about late-model vans here; if yours is earlier the wiring is similar but I won't be holding your hand, you'll have to be able to read your diagrams. Early models also only had 2-speed fans.
On a late model, how to do it depends a lot if you have an AC-equipped van or not. Non-AC just has the two speeds controlled by the radiator switch, and an actual two-speed 300w motor. The low speed is directly switched at the rad switch, while the 2nd speed is relay-controlled. If you wanted to trigger the 2nd speed relay, here's your skiz for an 86-up:
But if you have AC, there is a much more powerful 450w motor, one-speed with a dropping series resistor remotely mounted that makes for three fan speeds.
With the three-speed AC setup, you can always switch on the low speed manually by just turning on the AC temp switch to its lowest value, just a noodge away from off. This will leave the fan on constantly at lowest speed, but won't cycle the compressor enough to make any difference.
So, I already had that available, but at that low speed there still isn't much cooling. It's probably equivalent to moving not ore than 10mph. So I wanted to access the second speed, which cools really well but isn't as obnoxious as the 3rd speed, which positively roars.
The second speed with AC is relay-controlled, and normally only operates when the AC is on, so it was easy to patch some power to that relay coil with a tiny dash switch and small wires. I took the switching power off the X-bus load-controlled connection right at my headlight switch, so it only works if the ignition is on and stops during cranking to free up current. The $5 FLAPS toggle switch has a bright blue LED which I can see even in daylight so I'm reminded that it is on:
Here's the skiz:
I indicated "X"- power as just coming off the panel. You can grab X-power off the extra pins on the back of the late fuse panel, G1 or G3. If you want to mount your switch near the headlight switch as I did, the X feeder is the Black/yellow wires, there are two, a fat one and a thin one both joined to one connector at the back of the switch plug.
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syncrodoka
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Joined: December 27, 2005
Posts: 12397
Location: Santa Cruz, CA
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| Posted: Tue Sep 15, 2009 3:45 pm Post subject: |
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| Thanks tencentlife, I will have to add this to my to do list. I will be doing it to turn on the fan during wheeling adventures when vehicle speed is low but cooling is needed. |
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10151
Location: Abiquiu, NM, USA
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| Posted: Tue Sep 15, 2009 6:34 pm Post subject: |
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Glad I could help. I do like to stay ahead of cooling when we're crawling over rough terrain.
As a general rule for vehicle electric mods, if you check the diagrams and see that something has a relay controlling it, that is usually because the circuit has a pretty high current draw. But a relay coil uses less than 200mA, so it's simplest and cheapest to just power that relay coil with a small switch and light-gauge wire.
_________________
Shop for unique and useful Vanagon accessories at the Vanistan shop:
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Please don't PM here, I will not reply.
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crazyvwvanman
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Joined: January 28, 2008
Posts: 10452
Location: Orbiting San Diego
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| Posted: Tue Sep 15, 2009 7:07 pm Post subject: |
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If you have a Syncro without A/C neither wiring diagram 10c provided will likely apply. Bentley page 97.200 shows the special and simpler radiator fan wiring typical of these models. They have the big fan motor but only 2 speeds controlled by the radiator temp switches.
Syncros without A/C likely have no wiring connected to relay socket 5 even if someone stuck a relay there. The fan relay used in these is up above the ground stars.
Mark
| syncrodoka wrote: |
| Thanks tencentlife, I will have to add this to my to do list. I will be doing it to turn on the fan during wheeling adventures when vehicle speed is low but cooling is needed. |
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msinabottle
Samba Member
Joined: September 20, 2005
Posts: 3492
Location: Denver Area, Colorado
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| Posted: Tue Sep 15, 2009 7:30 pm Post subject: VAL 9000? |
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"I have the greatest enthusiasm for this mission, Dave. I think you need to go and repair the rear antenna, Dave. Did I tell you that I have the greatest enthusiasm for this mission, Dave?"
2010. The year Vans make contact.
Best!
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Vanagon Poet Laureate: "I have suffered in
many ways, but never, never, never in silence." |
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tencentlife
Samba Member
Joined: May 02, 2006
Posts: 10151
Location: Abiquiu, NM, USA
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| Posted: Tue Sep 15, 2009 7:56 pm Post subject: |
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Damn, Mark, always another variant I wasn't aware of. Even the non-AC 90's still used the 2-speed 300w fan, according to Bentley. The diagram on 97.200 shows non-AC 86-89, but nothing about Syncros, but you see far more of these than I do, I guess you'd know.
Why did they pull power off the 30 in the engine bay to power the fan in front? Didn't they put in the big feeder from the battery the others use? Odd. Vw's wiring decisions defy logic at times, but then it's never been their strongest suit.
Anyway, with that setup I doubt you'd want the full 450w to run manually, but if you did you'd just power the 2nd-speed relay coil. I take it with only one resistor the low speed is closer to the 2nd speed on an AC van, and if so that would be a more desirable speed to use constantly for crawling. If that were the aim, I think I would use a relay to do a run-around the rad switch, and power that relay coil remotely.
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Shop for unique and useful Vanagon accessories at the Vanistan shop:
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crazyvwvanman
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Joined: January 28, 2008
Posts: 10452
Location: Orbiting San Diego
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| Posted: Tue Sep 15, 2009 9:20 pm Post subject: |
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Yes, that is an error in the adjacent text, the power for high speed fan relay really comes right from the battery via a separate red wire. Same as the A/C models with the big fan.
I think the big fan 2 speed resistor gives same low and high speed as the 3 speed version, just no middle speed for the A/C.
I have only personally seen that 2 speed version of the 450 watt fan wiring on Syncros without A/C. I can't say for sure how broadly that setup was otherwise used. I remember looking it up in the VW parts data and finding that for Syncros VW only lists the big fan and big fan shroud, as late as 91.
Mark
| tencentlife wrote: |
Damn, Mark, always another variant I wasn't aware of. Even the non-AC 90's still used the 2-speed 300w fan, according to Bentley. The diagram on 97.200 shows non-AC 86-89, but nothing about Syncros, but you see far more of these than I do, I guess you'd know.
Why did they pull power off the 30 in the engine bay to power the fan in front? Didn't they put in the big feeder from the battery the others use? Odd. Vw's wiring decisions defy logic at times, but then it's never been their strongest suit.
Anyway, with that setup I doubt you'd want the full 450w to run manually, but if you did you'd just power the 2nd-speed relay coil. I take it with only one resistor the low speed is closer to the 2nd speed on an AC van, and if so that would be a more desirable speed to use constantly for crawling. If that were the aim, I think I would use a relay to do a run-around the rad switch, and power that relay coil remotely. |
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