84 Vanagon Radiator Fan Relay

Ethan5150 · Posted: Tue Jun 07, 2011 12:59 pm Post subject: 84 Vanagon Radiator Fan Relay

Can anyone tell me where the radiator fan relay is located in the 84 Vanagon? My temperature sensor seems to be working (5v) but my fan isn't kicking on even when the sensor is jumped. I'm assuming it's a relay problem but I'm not sure where that relay is. Anyone know or have any ideas?

***Is this the relay under the driver's seat?***
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

crazyvwvanman · Posted: Tue Jun 07, 2011 1:04 pm Post subject: Re: 84 Vanagon Radiator Fan Relay

The 84 rad fan has 2 speeds and the relay is only used for high. If neither speed works you have some other problem besides the relay. Did you replace the fuse?

The fan relay is kinda hidden, up high above the ground wires that plug in behind the fuse panel. There are 2 way up there, side by side. The second one is the coolant level warning relay.

Mark

Ethan5150 · Posted: Tue Jun 07, 2011 1:09 pm Post subject:

If I'm reading the diagram right, fuse 7 is for the fan, and it's fine (as are all the other fuses).

Now I'm confused - I'm getting 12v out of my 87 post when the van isn't even on. Is this right? What should I be checking for?
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

crazyvwvanman · Posted: Tue Jun 07, 2011 1:31 pm Post subject:

Yes, #7. Did you take it out and put it back?

When you said you jumpered the sensor I assume you meant the wiring for the sensor and not just the sensor itself?

If you jumper 2 wires at a time until you have done all three combinations the fan should run in two of them. At the very least you should hear the relay clicking when you jumper the pair for high speed. Does it click?

The fan needs power and ground. Yours has a 3 pin connector down near the motor. You can unplug it there for testing. One wire is ground, one wire is low speed power in, and the other is high speed power in.

Mark

Ethan5150 · Posted: Tue Jun 07, 2011 1:39 pm Post subject:

Thanks for all your help!

Here's what I know:

- the ground at the fan is good (checked continuity to battery)
- there is NOT continuity from the 87 post to the red wire at the fan
- the 87 post is giving me 12v even without the van running (I thought this was supposed to be triggered when the relay kicked on?)

***UPDATE - my mistake, it's the 30 that's giving me 12v, not the 87 - I'm going to check the 87 now ***

I'm a little unclear what you mean when you say I should hear the relay click when I jumper for high speed? As for the fan itself - it runs just fine when I just give it straight power - it's just not kicking on when I don't jumper it like that...

...and yes, I meant the wires at the sensor, not the sensor itself...
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

Ethan5150 · Posted: Tue Jun 07, 2011 1:50 pm Post subject:

Is there any reason I can't just run a hot 12v to my 86 post to see if the relay flips? Is there a better test I should do?
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

crazyvwvanman · Posted: Tue Jun 07, 2011 2:18 pm Post subject:

One of the three wires to the rad temp switch should have 12 volts always, key on or off, always 12 volts. If you jumper from there to either of the other 2 wires the fan should spin. One of the other 2 wires goes directly to the motor and spins low speed. The third wire connects to the relay coil and clicks the relay on so the relay powers the motor at high speed.

Measure for 12 volts at the rad temp switch plug. Then keep measuring there while you jumper over to the other wires one at a time. Does the voltage drop much? How much? Do you ever hear a small clicking up behind near the headlight.

The fan relay is up high under the dash at the left end. Very hard to reach with test probes. Are you looking at the right one?

Mark

Ethan5150 · Posted: Tue Jun 07, 2011 2:57 pm Post subject:

Ok, well I've found the relay and done a bunch of testing. I'm confused though - is the rad therm switch 2 the one that's plugged into my thermostat housing or is that switch 1? I haven't located any switch in the front of the van yet - just the fan and plug...

The switch (sensor) that's plugged into the thermostat housing is only showing 5v across it...this doesn't seem right...

When I jumper across the relay (from source to load) I get my 12v at the fan plug, but I'm thinking the relay isn't getting triggered...
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

whafalia · Posted: Tue Jun 07, 2011 3:14 pm Post subject:

Pull the lower grill and you'll see the 3-wired plug to the right. You should find 12 volts at one of the wires and can jump it to the others to confirm a dead radiator temp sensor.

crazyvwvanman · Posted: Tue Jun 07, 2011 3:40 pm Post subject:

The radiator temp switch is screwed into the front of the radiator, behind the lower grill on 83+, (behind the upper grill on earlier years).

Mark

Ethan5150 · Posted: Tue Jun 07, 2011 3:41 pm Post subject:

Ok, now I'm getting somewhere. I jump from the hot wire on the fan switch to the 2nd wire and the fan spins. So how do I confirm for sure that the switch is bad? In other words - how do I ensure the switch is getting triggered when it's supposed to?
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

sc1out · Samba Member Joined: September 27, 2010 Posts: 141

whafalia · Posted: Tue Jun 07, 2011 5:15 pm Post subject:

I think you just confirmed it. When last I replaced this switch I thought I'd test the new one using a heat gun and an infrared thermometer. Don't try this, I broke the switch. I did learn the failure mode though, the base of the switch is a brass plug with the outer part where the contacts are bushed into it. After breaking the switch by trying to heat it with the gun the outer part was ever so slightly cocked, pushed out at a slight angle, such that the contacts within couldn't contact. I think you're in for a new switch but maybe another possibility is clogged radiator. Is heat fairly even across it?

Ethan5150 · Posted: Thu Jun 09, 2011 6:46 pm Post subject:

Well I made some progress today. For starters, the sensor in the thermostat housing (new) appears to be bad - it's showing my engine way hotter than it should (operating at ~180' but showing the needle almost pegged). This was what got me thinking the fan switch was bad. I replaced the switch and realized after the fact that the fan probably wasn't coming on because my engine wasn't as hot as the gauge said it was. I metered the radiator and the fan kicks on in the 200' range - just as it's supposed to. So I'm off to Oreilly to replace a faulty sensor. I'm having another issue with my oil pressure light and idle surging but I'll start new topics for those. For now, my radiator fan woes seem to be over...
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

klucz · Posted: Thu Jun 09, 2011 8:00 pm Post subject:

There are also lower temp fan switches listed by some vendors. Been thinking about getting one for my '84.

http://www.busdepot.com/view.jsp?model=43&category=13&group=92&prodgroup=753

http://www.bus-boys.com/
I. 321-959-481D 85 Fan Switch, 3 Terminal, Dual Stage - 85 to 93C (Colder Than Original Temp) Wasserboxer 1983 to 1991 $12.00
I. 251-959-481K Fan Switch, 3 Terminal, Dual Stage - 76 to 93C Latest Replacement (Even Colder) For Wasserboxer 1983 to 1991 $9.95
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84 Westy 4spd sold

Ethan5150 · Posted: Thu Jun 09, 2011 8:44 pm Post subject:

This is very interesting - do you think that running the fan more often will burn out the motor faster? Is it really necessary? The idea of keeping it cooler certainly appeals to me...
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"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

klucz · Posted: Thu Jun 09, 2011 9:10 pm Post subject:

Well, I don't think a cooler fan switch is necessary, there are lots of Vanagons with the higher temp switches on the road that seem to do ok. I've heard my fan cycling on/off repeatedly in certain hot driving situations and thought that it might help maintain a more constant temp if the fan kicked on sooner. I think a manual override switch would be even better though.
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84 Westy 4spd sold

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52391

I have run a 251-959-481-75 low temperature fan switch for most of the two decades I have owned a Vanagon. When matched to a stock thermostat it seems to work very well. I have used them on all three Vanagons I have owned including a 2.2 Subi conversion.

Ethan5150 · Posted: Thu Jun 09, 2011 9:46 pm Post subject:

Good to know. I think I'm going to do it. Cooler seems better...
_________________
"It is no measure of health to be well adjusted to a profoundly sick society" - Krishnamurti

Wildthings · Samba Member Joined: March 13, 2005 Posts: 52391


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