I want a simple way to have a switch to control the rad fan

[Mike Robinson]

I do this for my AAZ diesel Westy, when I start climbing a hill and the temp starts going up, flick the switch and it stops it from getting too hot. Over heating my Diesel engine is right up there on things I don't want to experience.

I am sure the switches work, but it is nice to have a bit of control just in case.

When you look at the switches there are two wires going into each switch. As the switch is activated the circuit closes, and power to the fan happens.

So get a couple of piggy back spade connectors and attach them to each of the terminals. The old wiring stays in place so the 'auto' function still is there, then run two wires back to a toggle switch you have mounted somewhere on the dash. Activating the switch does the same as the auto temp thing.

Super easy.

If I remember correctly on the '82 model that I have the switch is an earth switch ie negative so no current goes through it so any toggle switch from you FLAPS will do.

Mike
'82 Westy Diesel.

[Paulbeard]

[DuncanS]

Mike--He has a WBX--Not the diesel you have. Confused as you said the the '82 has a ground switch--82 was air cooled. Just checked Bentley--the '87 is definitely NOT ground activated. As I said, this is not a simple job to be reliable and safe. Yes, you can just bypass the thermostat switch, but dealing with this and making sure you get the right wires can also cost you your ECU if you make a mistake.

[crazyvwvanman]

He is mistaken about the 82 diesel watercooled rad temp switch switching the ground side. Also it is false that the earth/negative side carries less current than the positive side, since we are talking about DC automotive circuits.

It is simple to hot wire a switch to turn on the fan but there is some risk to doing so and thought should be put into it. I would prefer a switch using a separately fused diode protected alternate power source, tied to the high speed fan relay control pin wiring. So a key-on power wire to the switch, through a fuse and diode, then a single wire from the new switch run to the red/blue wire at the 3 pin rad temp switch wiring. (this is for 83+, as 82 is a little different )

Mark

[Marcq]

[Marcq]

Thanks for all the feedback. it's just that I have heard of people doing it and thought it was a good idea specially in my case where I live, not uncommon to be faced with traffic and 100-120 degree temp in the summer

I ear a lot about how great the system works and yet you see people doing all king of engine conversions, weird!

Marc..

[MarkWard]

I have found the stock 2 speed rad fan system to work quite well. There are very few operating conditions where the first speed rad fan can't keep up with the heat idling in 110 F degree in a traffic jam. Going down the highway on the same day, the fan is probably not even running and engine temp is maintained by the air flow across the radiator.

I have been in two situations where the high speed radiator fan does operate. One is when I have been tooling down the highway and decide to stop for fuel. If I get hung at a couple stop lights at the exit, the fan has clicked to high, but very rare.

The other time the high speed fan kicked on was climbing Pikes Peak. Slow speed and gaining altitude. Low speed was working fine and a few times high speed would click on and the fan would cycle between high and low as expected. A pressurized cooling system with the proper mix should be fine to 250F before boiling over. Its a bit startling when the rad fan does come on high. As I said its very rare and sounds like a hover craft. Don't know that I would want that running continuosly.

I'm with the others that if you are not familiar with automotive electrical probably best not to learn on the one system you need functioning correctly to keep the engine alive.

edit: engine conversions have nothing to do with the Vanagon's cooling system. As far as I know, including my engine conversion, I am using the stock vanagon cooling system as designed. I am probably making twice the HP and torque of the stock engine, yet the cooling system works fine. If anything the Vanagon cooling system is over designed based on my experience.

[kamzcab86]

[Dampcamper]

The only fan-related cooling issues I've ever had were when the high-speed relay failed (in my diesel Rabbit), and when a thermal switch failed on a Vanagon. In both cases I made up and used a jumper wire to force the fan on and completed my trip that way.
I've thought about an emergency forced-fan switch for my Vanagons (The Rabbit met a deer at highway speed so is no more but neither is Bambi) only because the thermal switch is kind of awkward to access.
But as noted above the system works pretty well as designed so haven't worried about it enough to implement a permanent circuit. I do carry jumper wires for the fan thermal switches just in case. A scrap of #16 wire, some crimp lugs, and away you go. I'd wrap electrical tape around the connectors after installation to minimize risk of shorts.
A switch would allow you to turn the fan off when you stopped instead of having to pull the jumper wire, there is some attractiveness to that.

[dobryan]

If you think you need a switch because you think it is overheating there is a problem with the stock cooling system or the temp gauge is not giving you accurate info. Either issue should be rectified vs adding a switch IMO. The stock cooling system is very robust, but old, and may need some components replaced.
_________________
Dave O
'87 Westy w/ 2010 Subaru EJ25 (Vanaru) and Peloquin TBD

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