The wiring on the aux/ ac fan is pretty thin. I would NEVER run a full sized efan (taurus, villager, etc) using the stock wiring. Basically if its powerful enough to cool your car its probably pulling too many amps to run safely on the 12-16 awg wiring thats in there. I wouldn't run anything larger than an 8-10" fan on that stock harness.

The relays and triggering system work just fine, and the sensor is quite reliable. It turns the fan on when the ac is on and above 195* for the auto switch and 207* for the turbo switch. There's a writeup about using the stock thermoswitch to trigger an aftermarket fan (it involves running larger wire and a relay).

If there is no signal from the thermoswitch and the wire is not grounded , the factory ecu will run the fan constantly, mine did, until it burned out. If you have a Haltech it doesn't seem logical that your fan should be running as you have removed the stock ecu and the only way the fan would get a signal is if it was intentionally wired into the Haltech...and if someone is gonna go through all that trouble, why wouldn't they program in a reasonable operating range?

As far as that coolant hose goes... ha! factory hose my ***. just get a straight piece of quality hose about 3' long and one of those bendable hose coils and you can figure it out. To avoid having to do this again soon, I also wrapped the hose in aluminum duct tape and foam insulation for copper pipes. Also, buy quality oil filters (such as mazda oem and K&N) they have a one way check valve that does puke oil all over the place when removed.

 

^ where would you recommended buying the hose, just the auto parts store?

 

I'm not running it as my fan , I use both I wired it to a relay with direct fused power with the cooling fans + as its signal. Works well rarely passes 1/3 on my s4 gauge , even beating on it . It also shuts off under acceleration due to the fact its controlled by the cooling fan module .

I'd get a hose at napa .

 

false

my S4 T2 base model had one, with 5 speed/AC and no power steering or ABS. some manufacturing plants installed them where others did not, it is a regional/options thing. basically what i can guess is if your car was produced for a certain region and had A/C it also had this auxiliary fan.