4th Gen Radiator Fan control help...

Strangerover · Post by **Strangerover** » Sun Nov 15, 2020 1:10 pm

Hi all

Hope someone here can help...

I have had a Link ECU fitted and set up in my H22 Gen 4, now giving 245BHP.

We have one issue to overcome, control of the coolant fan.

With the AC turned on, both fans work as they should.

But with the AC off, the main cooling fan does not engage.
We suspect this may be a ground issue as the ECU is using a simulated ground as opposed to an actual ground.

Looking at the wiring diagram, there is a control box in the system, but I cant find any info on it.

I have a UK 1996 model, so I have two coolant sensors on the block , seems not all models have the sensor on the thermostat housing that I have.

Any help advice welcome, also should the fan come on after ignition off while the engine is cooling??? my car has spent the last 2 years being restored, uprated so I cant recall.

Thanks

Post by **Vtecmec** » Sun Nov 15, 2020 5:03 pm

They all have the sensor in the thermostat housing, which effectively is just a switch to turn the fan on or off.

Sound like you have a ground issue, if you unplug the sensor and bridge the plug, the fan should come on.

Since it works with the AC on, it's probably getting it's earth that way, try giving the fan another earth and see if that works.