whatcop?

Alright this is a brief summary of how to hardwire your stock fan system. Even though you can fully turn up the fan in the tune it does not equal how fast it spins when you hardwire it. To give you all an idea when my fan was fully turned up in the tune I could barely feel it moving air passed my hand when holding it against the bumper vs afterwards I could stand 3-4 feet away and feel it drawing air passed my hand.

Also this will help cooling at speed which I've personally verified. My original wiring burned out due to the fan being turned up fully in the tune which happens in all C6s. I did have a casper electronics unit that allowed me to control the fan manually. At 70mph cruising down the highway I switched the fan system off from the high mode and noticed that coolant and oil both crept up about 5* each. Meaning that the hardwire should be effective to higher speeds since I can feel it moving air more aggressively than the tune or casper unit could command the system.


That being said lets get down to the easy/dirty/cheap part.

You will need:
40/60 amp 4 post relay
60 amp fuse (in-rush on the fan is somewhere around 50 amps)
60 amp fuse and holder
Heavy gauge wiring

1) You are going to cut the wires/plug(red and black) coming off the fan that is going into the silver box which is the pulse width modulation box (PWN) on the backside of the fan.

2) The red wire will be connected to the post on your 4 post relay using the heavy gauge wiring.

3) The black wire will be your ground wire that you will connect to a ground on the car. I used the one by the hydraulic shock for the hood.

4) The trigger wire(this is a post on the 4 post relay) should connect to either a manual switch that you will control or what I did was tap the intercooler pump hot wire which is right there and have that trigger the relay.

5) You will then connect a heavy gauge wire to the alternator post with the 60 amp fuse to the 4 post relay.

6) You run the ground from the 4 post relay to the same ground spot as the ground wire for the fan.

I have my intercooler pump turned on in the tune for immediate on with accessory or ignition so in-turn this signals my fan to also be turned on immediately.





Courtesy of gkzr1

AMGTOZ

In your diagram, you have two yellow circles, and in between them you have "Aux Lights"
Should that be Aux Fan's?

whatcop?

Yes you are correct in that will be the fans. I just pulled that one off Google images.

gkzr1

if you want to update original post

The boss

Just to make sure I understand correctly, does the casper electronics unit make the fan spin as fast as hard wiring? I have the casper unit and I use it in city driving or traffic jam. This car is only used for cruising and less then 3000m per year. Should I be scare about harness overheat at the fan or module?

gkzr1

My Caspers harness melted.

whatcop?

It will melt it according to Casper electronics and no it does not spin the fan as fast as hard wiring.

FlipRay

So question now, since you bypassed the fan module, did you get some kind of CEL on the car?

whatcop?

You will get a message on the DIC saying service charging system but any tuner can get rid of that.

KM177122

This is great, thank you!

SIK02SS

Any update to this mod? Does it wear the fans out or is everyone's fans still working great?

KM177122

Mine is still working great. I Have about 4-5k miles(to include some mexico runs and drive to and from TX2K17). Works great and doesn't throw a CEL or seem to damage the fan(that's probably mostly tune related, I never like to run things at 100%).

SIK02SS

Thanks! Have a feeling I'll be doing this as it heats up for summer

KM177122

It's a smart thing to do in advance. I unfortunately found out about it the hard way LOL! Took me not long at all to remove the connector from the wires and solder them together(3 wires in total). Too easy and works well.

whatcop?

Mine has also been fine. Never heard of a fan failing but in the event it does you can find used ones on the forum for dirt cheap.

Black E

2 questions,

What gauge wire are you guys using? A 60amp fuse holder that I found at Napa come with 8awg wire.

By "alternator post", you mean the post by the passenger side fuse box?

Thx

whatcop?

Is go with 4 or 6 gauge according to charts I looked up and amp carrying capacity. The post would be the one located directly on the alternator but you could use the one off the side of the fuse box as well.

HottubChampion

With this setup the fans will only have one speed which is full blast correct? How much noise does it produce?

whatcop?

Correct and it would be a smidge above high speed now when your car controls it through the computer.

SIK02SS

Had a surprise this morning on my way to work when smoke and an electrical smell was coming from the under the hood when I turned in the parking lot. The 60amp fuse to the alternator completely melted down. Guess I'll increase wire size and fuse rating.