Guys, I need some suggestions on how to wire up the fans on the FD. As you know there are four relays, low, med or high. I'm going to use one of the PWM signals as the ground to signal the relays but I'm not sure where I could input the PWM wire(ground). Can I use the existing relays to get a signal from the Haltech or do I have to bypass the stock relays and make new wiring? Your help is greatly appreciated. Also, how did you guys get the tach to work? I know you can use a auxiliray wire but where do you attach it to get a signal? What are the settings supposed to be? 2 rotor and ? %duty?



Aldo

 

I'm trying to wire up the fans to work individually according to temp. Unfortunately I can't get it to work. I'm assuming that PWM output 3 switches from voltage to no voltage dependent on temp. Currently the coolant temp is 50 degrees. If the PWM wire should provide a ground at any temperature above the low coolant temp of 30 degrees. Anything below that it should show voltage to open the circuit. What is happening with mine is that I don't see the signal changing depending on temperature. No matter what temp it's set at, it will show no voltage. Any ideas?

Aldo

 

This is how you wire a fan with the PWM.

 

In order to wire everything up to work as stock (3 speed fans) you'll need to make sure that the two thermowitches are still part of the loop. One of the switches is on the back of the water pump. The other is under the dash and is part of the A/C system. From what I can tell by the schematics the switch on the back of the water pump controls ground to the fans through one of the relays. If you've eliminated this switch when installing the Haltech you'll never get the fans to run as stock. You'll also need two PWM channels to trigger the low and med speed and the A/C thermoswitch, I believe, triggers the high speed.

At any rate it' a complex setup that IMO is much like the rest of the FD...cool but way unnecessary. IMO, wire the fans as Claudio has shown. It's still a little more complex than that because the stock fan motors are a four pole and not a simple two pole design. If you have a FSM there is an informative page in the cooling system section on how to activate the desired speed. I would wire them to come on at high speed only and trigger them through your own aftermarket relay. This will keep things simple which is a big plus.

 

Its alot easer just to make your own relay set up and run high speed. Also it looks better getting rid of the four stock relays. You can use the power feed to the stock relays and use pwm to turn it on.

 

you can also ground the stock relays to ativate the fans> 1+2+4 relay grounded will give you the high speed.(I think) you will have to try grounding 3 of them at the same time to find high speed)this is if nothing else is activating the relays..thermoswitch and what not. You can then activate the stock relay with the pwm, with inturn grounds the relay and activate the curcuit.

Hope this helps

 

Thank you gentlemen. I appreciate the feedback. Hopefully this weekend I can mess with it.

I'll probably just do what Claudio said. Since I live in Florida, High is always needed.

Aldo

 

Heres how I plan on doing my setup, maybe it'll help

 

I like the set up. Looks like I might try this. Need to get some relays.

Thanks

Aldo