anyone fitted a radiator fan switch?

[Pepperami]

I had a chicken switch fitted to mine when I had the engine swapped.

[tencentlife]

Like I said in the other thread it's not much good finding out your thermoswitch isn't working when the engines boiling and can't do anything about it.
Good idea tencentlife but a lot of UK vans are only fitted with a single speed fan without a relay, which are even more susceptible to failure without the backup of the second high speed switch contact.

Only one speed? Really? That's pathetic.

[AngeloEvs]

According to the Bentley manual all wiring digrams show a relay for the Rad Fan. The Schematics start from 1982 onwards with the single speed motor and a relay is shown. Unless they didn't fit one prior to this date....

[ermie571]

Angelo....I guess pre 82 is all Aircooled with no radiator or fan.
There are one or two originally air cooled running around now with a watercooled engine....wonder if they could be missing a relay??
Em
x

[bigherb]

According to the Bentley manual all wiring digrams show a relay for the Rad Fan. The Schematics start from 1982 onwards with the single speed motor and a relay is shown. Unless they didn't fit one prior to this date....

Bentley are USA wiring diagrams not accurate for UK models.
As you can see there are three versions of fans fitted to UK Models from 86 and the earlier Diesels 84-86 which is different again.

[AngeloEvs]

That should go in the wiki.........dear oh dear, I wonder how many of the 200W models suffer premature failure of the thermo switch...definitely worth modding those with a relay let alone a manual overide switch.......very useful to post that Bigherb. Where did you get the schematic from?

[tencentlife]

Yeah, that's a good idea, even with that lame-o 200w one-speed fan. That's still 16A going across the thermoswitch contacts, which is plenty. The switch is rated for that, obviously, but taking load off of it will only let it last longer. Then with the relay, you can add manual-triggering.

I think if I had only that 200w fan, I would look for a later two-speed at the least and upgrade so there is some decent cooling capability available; the lowest speed on our fans, which is probably analogous, is on at least a 30% duty cycle at idle, that doesn't leave a lot of reserve capability for when any actual power is being made.

My comments can only pertain to N.American models since that's all we see; I figured you all would have some differences, I know AC is not popular there but it is here so on 86+ vans it's almost standard equipment. I also figured you all would have some different shop manuals since Bentley is just the authorised US publisher. But even here, in every variant the lowest fan speed is powered directly off the thermoswitch, while there is always a relay for the higher speeds.

Anyway there are a lot of ways to do a manual switching setup, but the general wisdom doesn't change and electrons only speak one language. If your aim is to power a high-current load remotely, running light triggering wire to a suitable-duty relay closer to the actual load is always best practice and will deliver full voltage to get the most work out of the load, whether it's lights or fans or whatever.

[Doctor Foster]

E D I T. Posted reply just after previous reply was posted.......but will leave as is......thinking pretty much the same.

You can take a feed from the ignition side of the fuse box, via a switch to the coil feed for the rad fan relay (terminal 86) colour coded R/Bl behind the relay......pretty sure thats how I did mine but its been a while. .....useful for checking every so often that the fan actually works OK!

I remember getting a real lambasting for doing this from the guys on Brickwerks some years back.......modding a VW doesn't always go down well but, what the hell.......it's my bloody van! Went up Porlock HIll and the fan didn't come on ......earth spade had overheated and crumbled away (at the crown next to the fuse box) and hadn't been aware of it. I see a big hill looming and I flick the switch.......just to make sure......

Easy enought to do which ever method you use but don't try and feed the Fan directly using a switch......it will be foobarred in no time at all.....take a fair bit of current those Rad Fans!

I have located the radiator fan relay (position 5) on fusebox. Can only get it to switch to second stage fan from this point If I connect 12v to the red/blue wire . Though not a problem, just very noisy!!
Is there a connection for 1st stage fan from this relay? Im happy to stick with the 2nd stage mind.

Cheers

[peasant]

People on german forums who have done this, urgently recommend putting a beefier ground wire on the fan motor itself.
Apparently what's there already is usually in an advanced state of decay, not really designed for prolonged use anyway and tends to get a tad hot, hot, hot if you have the fan running for minutes on end.

[AngeloEvs]

.....and the Earth terminates at spade connector at the crown next to the fusebox which overheats and crumbles....should be bolted to chassis with an eyelet.

[Doctor Foster]

Whats the best way of tapping into the wiring on the rear of the relay? Its a plug type connector so no spade terminals

[AngeloEvs]

find the wire with the correct colour code (in the schematic earler in the thread\0....I can have alook at mine and take a piccy if it helps

[Doctor Foster]

find the wire with the correct colour code (in the schematic earler in the thread\0....I can have alook at mine and take a piccy if it helps

A pic would be great.

I dont mind it connected to the 2nd stage fan. How do I tap into the wiring?? best method??

[Dantes]

Can anyone recall if it is possible to simply connect a switch to the the 30 and 87 relay connector? this brings on the fan but not sure if the Amps of work are too much for a little switch. Is connecting to the 85 or 86 points any better or just wire to the thermo switch on the radiator? Any help appreciated. Ta.

[bigherb]

You could do as long as you use a 30A rated switch.