Unreal

You can fly out to Phoenix and do my car and enjoy some gorgeous upper 70s for a weekend.

c6 use PWM to control fans so that is why it would need a switch, c5s just use a relay if I recall correctly with a computer signaled on/off.

Thoughts on this? Looks like painless may have something that works
http://www.painlesswiring.com/webcat...v.php?sl=30118
http://www.summitracing.com/parts/prf-30118/overview/

And a PWM controller fan setup wiring kit too
http://www.painlesswiring.com/webcat...v.php?sl=30142

ajrothm

Hey Doug, do you think C5s are plagued with the same voltage issues to the fans? My car has always ran hot since I went to the dual spals... Maybe their not getting enough juice..

The best way to wire the fans is get power directly off of the alternator stud, to a 50 amp bosch relay, then to the fans. Trigger the relay off of a temp switch, toggle switch or even the factory ecu signal (if its a ground signal).

I may look into experimenting with this this summer... Just force the fans on all the time over a certain temp.

This is how I did my 71'.


It has a Lincoln MK8 fan that pulls 50 amps at start up and 35 amps continuous.... Been wired up for 4 years and no issues...car always stays cool. I have it wired to the temp switch, the AC pressure switch and a toggle switch for the track. I may wire the Z06 up the same way and see if it improves cooling.

LTstewy8

Thanks, I didn't know about the c6 being PWM. I think there must be a way to make it work, but I'm no EE. I took a quick look at a 2010 camaro OS with HPtuners and noticed you can modify the fan PWM frequency. By setting the frequency to 0 Hz, would that disable the PWM function and allow the use of a relay like I mentioned earlier? Is frequency inversely related to the amount of time between pulse widths?

BLOWNBLUEZ06@RKT Performance

I'm guessing you could also run the PWM output to a standard relay with a capacitor in parallel and a quenching diode to stop any back EMF and help with the chatter and also accomplish the same thing. The larger the cap, the better chance of it working.

Skunkworks

Not having actually measured PWM output to fan speed module… I’d assume it follows GM typical design philosophy, that being a TTL (5V) CPU output with current limiting resistor for protection. If as described, then it will not pull in (turn on) a standard relay (12V).

A SSR (solid state relay) 5V input will/may work, but likely at too low of a frequency not to be annoying (audible sound) and not have adverse fan life issues. The fan speed control module likely has additional intelligence that converts PWM signal from E38 to a different PWM (higher frequency) with some overload protection.

bradenW

Everything the above poster said sounded like rocket science to me..haha I was just reading this thread the other day thinking I was lucky to have no issues...and today mine started. Go figure. I have a manual high/low/off toggle switch on mine and can only get the fan to operate on high with the switch. It still supposed to turn on automatically like factory at a preset temp but isnt all of a sudden. Buddy diagnosed the switch and relay and they check out. Controller going bad on me? I know next to nothing about this..

DSteck

There's no way a mechanical relay would keep up with a PWM frequency.

I already know I can make my own driver for the fans capable of 50A continuous current and 100A burst. I have an ECM sitting here. I could very easily scope it.

Using a SSR would probably be fine if the 128Hz thing is their. As far as hearing the switching, it'd be drowned out by other stuff anyway.

Corvettinator

All of this wiring and ECU talk frightens and confuses my caveman brain.

But I had *two* fan control unit failures in 2 weeks, and finally convinced my dealer to remove the freaking connector and direct wire it. They said it wouldn't be covered by warranty if it fails again. I nodded and smiled, not having signed any such waiver.

Anyway, so far, so good, knock on wood.

I ordered one of those manual selector switches from Southern Car Parts just in case another control unit fails.

5 Liter Eater

I've since cleaned up the ghetto'ness of this and added another relay for the dual fan setup but just to prove I beat Doug to it by a couple years here's the post.

http://forums.corvetteforum.com/c6-t...ontroller.html

RoadRebel

You can set the ECM Fan controls to "discrete" and the PWM Freq to 128HZ and you can drive a relay from its outputs. You can also change it to 2 fans instead of the factory single and drive from the 2 ECM pins separately.

DOUG @ ECS

Aaaahhhh, what a you know?!?


Thanks Phil, I'm sure that will help someone out in the future.

5 Liter Eater

That is great info Phil!

DSteck

Discrete is for peasants.

ravill

I put an 8" fan INFRONT of the condensor to push extra air in with it's own temp controller that has the fan turn on at 190.

So far, so good.

edge04

how did you connect that to the condensor? Who makes that fan? Is there also a bypass that only allows this to turn on when a/c is on? Are you on stock radiator? Thanks

Le Mans Z06

Hey Doug do you think I should be concerned with the fan module wiring harness connection burning up with my setup?

Unreal

You can see the fan mounting pad/plastic push things that are common on mounting radiator fans. You can get them at any autoparts store. A plastic thing slides through and a clip on the back side.

DOUG @ ECS

They burn up on stock cars so I would say keep an eye on it. Look at it during oil changes, if it's getting burnt up it's easy to see.

ravill

Here you go. Regarding the "bypass" so it comes on when the A/c is on, you have to find the power wire going to your A/c compressor and tap that wire.

ZBADESTZ@Straightline

What do we need and have to do to run this thru stock computer and what settings do we need to put on?

Thanks