External water pump for K-series

[rj]

Where do you find those wires?

[rj]

Kevin,

Having had a look at your previous post I was wondering if your fan could be wired to run regardless if the ignition is on when the VW thermostat kick in at 2nd stage?

If it is, this will cause trouble unless there's a diode preventing to feed battery +ve to the green wire. You may have noticed that the engine tends to run on when the fan is on and you switch off ignition. This is because the motor works as a dynamo.

The black wire on the switch usually goes to the fan, the fan has another black wire that is just an earth. The red is non standard.

I have been thinking of altering the wiring so that the green is a direct +ve feed only swithced by the master switch to make fan and pump run on even if ignition is off but not yet done so.

[CageyH]

The wires are on the EWP80 harness.

As far as I understand it, the thermoswitch will switch to earth when the coolant gets hot, so if I connected both the red and green wires to the battery, the pump will operate without the ignition on if the coolant is hot enough.

 

Connecting the green wire to 12v source controlled by the ignition would mean it only runs when the ignition is on.

 

I have been thinking so putting a diode in my fan feed to stop the overrun of the engine, but normally I wait until the fan stops before I turn the car off.

[rj]

The thermo switch will then, if no diode is fitted, feed the green wire with battery +ve until the temperature is below the 2nd stage cut off. This will keep the engine running.

I don't remember how the EWP80 wiring was initially. I ended up making my own where the thermo switch in the water rail switches earth. This is to prefent fire in case the insulation of the wire is damaged. After all it's just above the primaries.

[CageyH]

The installation is finally finished.

The relay sits in the spare relay slot in the fuse box. The switched positive is wired to the ignition barrel, and the positive feed direct to the battery. The earth is wired from the temperature switch, through a manual override switch back to the relay. 

I had a dribbling hose, so I had to drop the coolant to clean the pipe and refit. After this was done, I went out for a spirited drive. On returning home, I am happy to report that the pump does switch itself on while the car is idling, but the temperature quickly drops with the fan running.

I have tidied the wiring up under the dash a bit, and fitted my DRE shift light (been meaning to do that for ages after it was sent back from repair).