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insyncro Wed Jun 13, 2012 6:58 am

I have searched, found nothing and while transferring my files from one computer to another have lost some old data, this wiring upgrade schematic unfortunately... :cry:

Can someone post a link, diagram or just explain the proper way to connect a toggle switch to turn on the rad fan.
I am going to do this in a carat van and do not want to just turn on the AC.

I still want the thermo switch to be inline and the AC to activate it as well.

Ideally I would love to have different speeds with the toggle and I have multi position toggles, but just on off works for now.

Thanks in advance.

crazyvwvanman Wed Jun 13, 2012 7:26 am

The simplest way is to use the switch to trigger the high speed fan relay. That way the switch and its wires don't have to carry any real current. This also bypasses the failure prone fan resistor from your manual fan setup, assuming an 86+ that came with factory A/C.

Mark

insyncro wrote:
Can someone post a link, diagram or just explain the proper way to connect a toggle switch to turn on the rad fan.
I am going to do this in a carat van and do not want to just turn on the AC.

I still want the thermo switch to be inline and the AC to activate it as well.

Ideally I would love to have different speeds with the toggle and I have multi position toggles, but just on off works for now.

hdenter Wed Jun 13, 2012 7:27 am

Not sure how others have done it, but the PO of my van did it like this.

He mounted a weather proof relay behind the grill close to the thermo switch wired to the hot lead in and the fast speed out. He then ran the control lead from the ignition to a toggle and then to the relay. This way, when I trip my toggle, the relay jumpers the thermo and runs the fan. The existing fuses still function for the fan and the toggle. Works great! Hate to see the needle climb when I am stuck in traffic and waiting for the thermo to reach its threshold and kick on. The thermo does work and every once in a while I forget that this van has the over ride and the fan kicks on when things get hot enough. Good Luck!

Hans

jstar89crx Wed Jun 13, 2012 7:27 am

I have a 3 way low/off/high switch in my van for radiator fan. You will want to use a relay for the high side of the switch. I did mine a couple years ago, I feel like all the existing wiring and switches and resistors are behind the front grille, I ended up connecting to these and ran my wires into the van to a switch mounted in the instrument cluster. Unfortunately I am away from my van for a bit. You can PM me later this week if someone else doesn't have the info you need and I will go take mine apart to remind myself how I did it. Good luck.

insyncro Wed Jun 13, 2012 7:32 am

Thanks Everyone.

Any pictures, part numbers or schematics would really help.

I've got it under control and will use Marks method first, but would like to keep the info. flowin here for others who may have more questions.

insyncro Wed Jun 13, 2012 7:35 am

crazyvwvanman wrote: The simplest way is to use the switch to trigger the high speed fan relay. That way the switch and its wires don't have to carry any real current. This also bypasses the failure prone fan resistor from your manual fan setup, assuming an 86+ that came with factory A/C.

Mark

insyncro wrote:
Can someone post a link, diagram or just explain the proper way to connect a toggle switch to turn on the rad fan.
I am going to do this in a carat van and do not want to just turn on the AC.

I still want the thermo switch to be inline and the AC to activate it as well.

Ideally I would love to have different speeds with the toggle and I have multi position toggles, but just on off works for now.

Yes 1990 Vanagon Carat with factory AC.

The resistor is behind the drivers headlamp...where is the hi speed fan relay located :oops:

fairweather Wed Jun 13, 2012 7:45 am

10c has posted a how-to with diagrams, try searching with his username.

crazyvwvanman Wed Jun 13, 2012 7:45 am

The high speed relay for that model is by itself, hidden up high on the left end behind the dash. You don't need to get to it though. One of the 3 wires from the rad temp switch is the relay trigger wire. If you slice your switched wire into that one the switch will trigger the relay. The wire from the rad temp switch is the smallest one, red/blue.

The relay only needs about 1/10 of an amp so the switch and switch wires can be small.

Don't use a lighted switch or at least don't ground the switch if it is a lighted type.

Mark

insyncro wrote: Yes 1990 Vanagon Carat with factory AC.

The resistor is behind the drivers headlamp...where is the hi speed fan relay located :oops:

insyncro Wed Jun 13, 2012 7:48 am

Thank you Mark.

I will try to post my work on this as time permits.

Much appreciated :!:

presslab Wed Jun 13, 2012 8:36 am

Is there a technical reason to add a manual switch if the rest of the system is working fine?

I could see it relieving psychological tension for those that worry about the needle; so in this case, why not. In newer cars, the temperature gauge will hold steady even though the actual temperature can fluctuate quite a bit. The designers realized it's human nature to worry about such things, even though it doesn't matter to the engine.

floggingmolly Wed Jun 13, 2012 8:45 am

presslab wrote: Is there a technical reason to add a manual switch if the rest of the system is working fine?

I was thinking the same thing. Kinda like my post on the low temp thermostat.

presslab wrote: I could see it relieving psychological tension for those that worry about the needle; so in this case, why not. In newer cars, the temperature gauge will hold steady even though the actual temperature can fluctuate quite a bit. The designers realized it's human nature to worry about such things, even though it doesn't matter to the engine.

I was thinking about this during our last trip. I was wondering why the needle on the van is constantly moving up and down (well, not constantly but you know what I mean) and why on newer cars it just come up to about half way and stops.

insyncro Wed Jun 13, 2012 9:05 am

The van is dyno test mule for various engine conversions, has a cooling system I have updated for my purposes and will not see the road ever again.

I am testing a bunch of different scenarios with this van.

Yes, being able to turn the fan on and off, without the thermo switch engaging or having the AC engage it, is something I personally want, to be able to test different things.

Call me crazy :lol:

Wildthings Wed Jun 13, 2012 9:10 am

floggingmolly wrote: presslab wrote: Is there a technical reason to add a manual switch if the rest of the system is working fine?

I was thinking the same thing. Kinda like my post on the low temp thermostat.

presslab wrote: I could see it relieving psychological tension for those that worry about the needle; so in this case, why not. In newer cars, the temperature gauge will hold steady even though the actual temperature can fluctuate quite a bit. The designers realized it's human nature to worry about such things, even though it doesn't matter to the engine.

I was thinking about this during our last trip. I was wondering why the needle on the van is constantly moving up and down (well, not constantly but you know what I mean) and why on newer cars it just come up to about half way and stops.

My gauge reads pretty much rock steady, but I use a low temperature fan switch that kicks the fan on as soon as I slow down instead of waiting until the coolant temperature begins to climb.

insyncro Wed Jun 13, 2012 9:12 am

Wildthings wrote: floggingmolly wrote: presslab wrote: Is there a technical reason to add a manual switch if the rest of the system is working fine?

I was thinking the same thing. Kinda like my post on the low temp thermostat.

presslab wrote: I could see it relieving psychological tension for those that worry about the needle; so in this case, why not. In newer cars, the temperature gauge will hold steady even though the actual temperature can fluctuate quite a bit. The designers realized it's human nature to worry about such things, even though it doesn't matter to the engine.

I was thinking about this during our last trip. I was wondering why the needle on the van is constantly moving up and down (well, not constantly but you know what I mean) and why on newer cars it just come up to about half way and stops.

My gauge reads pretty much rock steady, but I use a low temperature fan switch that kicks the fan on as soon as I slow down instead of waiting until the coolant temperature begins to climb.

Please post the part number of the switch you are using.
Thanks for the info.

insyncro Wed Jun 13, 2012 9:15 am

http://www.van-cafe.com/home/van/page_1349

Thanks Jay.
Posting for others to check out.

presslab Wed Jun 13, 2012 9:20 am

Wildthings wrote: My gauge reads pretty much rock steady, but I use a low temperature fan switch that kicks the fan on as soon as I slow down instead of waiting until the coolant temperature begins to climb.

Is this what you have?

http://www.van-cafe.com/home/van/page_1349_223/fan_controller.html


And what is your reason for using it?

I like a vehicle speed fan controller, it's an interesting idea. The Subaru ECU has this intelligence in it. I sometimes wish I'd hooked it all up, so with A/C on the fan isn't powered going down the freeway. Right now I'm just using the Vanagon thermoswitch and the normal Behr A/C wiring.

presslab Wed Jun 13, 2012 10:58 am

insyncro wrote: The van is dyno test mule for various engine conversions, has a cooling system I have updated for my purposes and will not see the road ever again.

The radiator fan will not flow near the same amount of air that a typical dyno fan will flow. For example, the link below shows two 1200W fans. The Vanagon fan is at best a single 450W fan. I'm not sure your override will have the result you desire.

http://www.dynoblower.com/product.sc?productId=1&categoryId=6

Wildthings Wed Jun 13, 2012 4:31 pm

presslab wrote: Wildthings wrote: My gauge reads pretty much rock steady, but I use a low temperature fan switch that kicks the fan on as soon as I slow down instead of waiting until the coolant temperature begins to climb.

Is this what you have?

No the switch I use is the same part number as the stock switch, but with a -75 suffix added. It works well with the stock (87C) thermostat.

Part #25195948175, available through Bus Depot and many other sources.

insyncro Wed Jun 13, 2012 6:00 pm

presslab wrote: insyncro wrote: The van is dyno test mule for various engine conversions, has a cooling system I have updated for my purposes and will not see the road ever again.

The radiator fan will not flow near the same amount of air that a typical dyno fan will flow. For example, the link below shows two 1200W fans. The Vanagon fan is at best a single 450W fan. I'm not sure your override will have the result you desire.

http://www.dynoblower.com/product.sc?productId=1&categoryId=6

I know and have the dyno fans.
I'm testing things like water wetter, Evans coolant and a few different other cooling and AC products.
Not just dyno tuning the engine.
Not all tests are being done while on the dyno and having the ability to run that fan without having any other variables changed with the motor, like the AC compressors pumpin is needed.

Syncroincity Wed Jun 13, 2012 7:12 pm

I'm putting in the same switch, because I'm running an intercooler radiator up front, and I want to be able to keep ahead of the heat load in slow speed / hi-boost situations like offroading.



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