Radiator Fan Testing Jumping Etc.

[paddywalsh11]

The WIKI page on testing the radiator fan quotes:

The electric connector pulls off and has three female spade connectors, jump the middle pin to each of the outside pins in turn (use a big paper clip), one side should bring the high fan on and the other should bring the low fan on

As a guy who didn't pay that much attention in school especially in electrics, how do i jump these pins, i have my paperclip ready. Could someone put the above into not layman terms but Paddy terms, e.g as simply as possible.

I am trying to find out if my thermo switch needs replacing, just don't want to make it worse, or get coolant everywhere.

Much appreciated

Paddy

[JonnyAtlantic]

Jumping is simply connecting the two terminals together in this case with the aid of paper clip. So paperclip touches both terminals at same time.

[paddywalsh11]

Thanks for the reply, I understand what jumping is, i don't understand how to go about it.
I understand the paperclip is going on the terminals of the male end. However with this in place the thermo switch can't get any power without being 'plugged in'. The female end of the 'plug' has a white plastic filler, thus not allowing it to be plugged back on if a paperclip is in the way.

Hope you can shed some more light on this.
Paddy

[Oldiebut goodie]

The idea is to test the fan by bypassing the thermoswitch. If it now works the chances are that the switch is fubarred with the remote possibility that the radiator isn't getting hot enough to cause the switch to operate.

[paddywalsh11]

How do i bypass the switch?

Apologies for the lack of knowledge on all this, i am just trying to determine if it is the thermo switch that needs replacing.

Paddy

[AdrianC]

Remove the lower grille.
Unplug the cable from the switch in the rad.
Ignore the switch in the rad. It's the _cable_ end you're testing.

With the red probe from your multimeter (set to about 20v range DC), poke around to find which one's got +12v, with the black probe against a good clean bit of metalwork as an earth. If none of 'em have, that's your problem.

Then, with a short bit of wire with bared ends (easier than a paperclip), stick one end in that +12v, and the other in one of the other terminal. You should hear the fan fire up. Now try the other terminal. You should hear the fan fire up differently - either louder if you hit the low speed first or quieter if you hit the high speed first.

If both work, the switch is dead.
If neither works, the fan is dead or the earth to it is bad.
If only one works, or the fan sounds the same, probably the low speed relay is dead or somebody's been playing.

[jamesc76]

R
If only one works, or the fan sounds the same, probably the low speed relay is dead or somebody's been playing.

Some vans only have single speed!!

[AdrianC]

R
If only one works, or the fan sounds the same, probably the low speed relay is dead or somebody's been playing.

Some vans only have single speed!!

With three-pin switches?

[paddywalsh11]

Ok, just went boldly and had a play with it today.

So the fan motor still works after a jump on the cable, so have ordered a new thermo switch.

When it comes to replacing the switch i have read if done swiftly only a tiny amount of coolant will be lost, if this is such a small amount will it need to be topped up?

If so, how? i have only found information on bleeding the tank and refilling (an empty tank).

Thanks for your help.

Paddy Walsh

[MidLifeCrisis]

Yep - if you are snappy with the change you shouldn't lose more than an egg cup full of coolant - just make sure everything is within an arms reach before you start and stuff an old towel/cloth at the base of the radiator to catch any dribbles.

As for bleeding - I just got the engine up to temp (so that there is coolant flowing through the radiator) then bleed using the bleed screw on the radiator (in theory the air that entered when you changed the switch should all have risen to the top of the radiator - so should be simple to bleed)