umm, if you read my last post you would of seen I already said sorry! and what are you adding to the thread? post whoring your self! and I didn't read the whole thread only replyed to post.

Well yeah ok its an interior post - but im going to say it anyway.

EF has a three mode/four relay thermo fan setup. both fans low, one low/one high and both fans high.

EL has a two mode/three relay thermo fan setup.
Both fans low, both fans high

If you start your car with the a/c off, no fans come on. Turn the a/c to low (cc or non cc with low fan speed) and the thermos will switch on to low.

If you switch the a/c fan speed to high, both thermo fans will switch to high.

On top of this the fans maintain a flow of air over the radiator - so if your engine heats up even if you aren't using the a/c, the fans will switch to low. If you thrash it and heat it up, the thermos will switch to high.

This setup works very efficiently, providing cold air to the condenser for cold a/c when you want it, and providing cool air for the radiator to regulate engine temp.

Why you would want to wire around this I don't know. Krytox - if your relays all work when you switch your a/c to high, the thermos will switch to high and you will get cold a/c - regardless of engine temp. If you have added extra relays to make your fans switch to high then I would be checking the four relays that you had there to start with.

^^^ Why?

umm, they don't go on high when the interior fan is on high.
The reason I have done this is for airflow and compressor life (maybe i don't want my interior on fast) I guess our family members 26yr auto and tractor AC experience is lacking some knowledge.

Either way, this isn't helping the person's question

In the EF's the air con and fan speed lines to the ECU have vastly different voltages with the climate/non climate versions, it's not very well known. This problem (thermos not running when A/C or high interior fan speed)will then appear when a CC conversion is done - EL's are not affected. You could fix the problem by installing a Fairmont ECU, but in Andrew's case, he would need to trick it with resistors as well as his car is a manual.
So don't be too hard on Andrew, his solution is simpler and works well - the A/C condensor does need decent airflow when stopped to help cool refridgerant and help keep the compressor head pressure/temperature down.

weell firstly - an apology to Andrew.

Anyway, I have very basic knowledge of the electronics that control interior fan speed and a/c/ compressor. I had some issues with my thermos ever since I bought my car (only ever had one thermo and it only ever span at high speed), but found our recently (using the diagnosis info on this site) that all I needed to do was replace a busted relay rather than just replace the fans which is what I though was the original problem.

In doing this I was able to get a basic idea of how the fans work and what triggers them. The most obvious trigger is that of the ECU which controls the fans in relation to coolant temp, but also the air-conditioning load also has a bit to do with the fans. For the a/c to work properly there must be a constant flow over the condenser - which is where the thermos come in. At low a/c load (low fan speed with say a/c selector on fresh air) the fans spin a low speed to provide air flow to the condenser, and will spin at high speed if you have a heavy a/c load like high interior fan speed and recirc switched on.

This was all done on my XHII S. The wiring for the thermos is based on the EL. Being the ute its likely there is a difference to that of the sedans as always the ute getting the poverty packs.

I think I've just repeated myself so I'm sorry if I have and yes this isn't helping the person who posted the original question but oh well now you all know why I said what I said and yes Im happy to admit I was probably wrong.

Cheers

You will find the A/C and ventilation electrics of the XH to be nearly identical to the non CC EL's. Only big difference is the airbox evaporator temp sensor. The controls look greatly different but the interface electrics aren't.

I stand corrected