tkkleinjr

Hey guys, hope you can help.....

I have a 2009 z06 and it is a beast. 606 at the wheels NA.

I have a Dewitt spal dual fan system that I ran off of the factory electric fan control module (efcm).

My issue:

My fans won't turn on. It is not the plug. I replaced the efcm and the fans turned on and worked as they should for about 3 hours. Then back to not working.

I think the dual fans are pulling to much power and frying the efcm.

Thoughts?

Dano523

Are the fans pulling there power direct from the battery through relays, and the PWM only controlling the relays only?


Or are the fans pulling therir power and being controlled by the PWM only.
If PWM only, which one (tell me it not the oem unit) and even with the upgraded PWM, you running the fan power directly to the battery terminal and not through the OEM PWM power wiring.

tkkleinjr

I am running directly off the unit that is in the passenger fender. (Quality Motorsports built it that way)

Should I build a system with 2 relays that turn on with the signal wire from the ecm?

Dano523

Photo of the set up would help.

Hence what the pwm is controlling and if its the oem unit, and if relays that the PWM is controlling, are they getting their power directly from the battery or using the power from the PWM oem power wiring isntead.

jft69z

There's some good info here:

https://www.corvetteforum.com/forums...fan-users.html

tkkleinjr

I don't have great pictures.




No idea what this wire is for. It's plugged.



This is the module I have the wiring going to the fans.

Three wires go into the module. Power and Ground, from fuse panel I would imagine. And a tiny third wire. From ecm?

Two wires come off of this. Power and ground to fans.

Is there any plug in aftermarket modules that would work in place of this?

Unreal

Nope, that is the factory fan module. Check all connections. You can't just by pass it because it is converting the PWM signal from the ecu to the fans. If you wire them direct to power they will be on all the time. If you do it off a relay you need a way for that relay to go on off like a temp sensor.

I would just find someone with stock fan/plug and swap that on.

tkkleinjr

I have checked every connection with a meter. Everything is good except the power off of the pwm is only reading 4.3 volts. I replaced it and it started working. Fans Ran like they should. Then back to not working 48 hours later. (One of those a track day).

zrracer

Maybe contacting the vendor would help?

Dano523

Will try to write you through this, but may have to do a diagram as well


PWM is going to get is power from the fuse box, so start by checking the fuse for it, a well as the connector on the back side of the radiator to make sure is not melted.



Also. pull the PWM connector to make sure you have not melted it as well.



Now if you do have power to M+ and M- on the PWM connector (12 volts) when its disconnected from the PWM and check with a multi meter across the two points on the connector, then you have power to the pwm.

Now tell me where the wires on the PWM connector 30 and 31 are wired to, and with luck they are not connected directly to the fans isntead.

If they are wired directly to the fans, then I need to to disconnect the pwm connector, and jump out the connection of M+ to 31 on the connector, then jump out M- to 30 on the connector. Hence with M+ and 31 jumped out first, as you jump M- to 30 on the connector, the fans should come on full blast.

If the fans does not come on, then you have a problem with the connector back to the fuse box power, or the connector to it ground point instead.

If the fans come on, then it real simple and you have a burnt out PWM from trying to pull too much power through it to run both fans.

Hence the OEM PWM can be used to control both fans, but this is done by it only using enough power to control relays, and the relays themselves pulling the power that they are going to send to the fans directly from the battery with their own power lines isntead.

tkkleinjr

Let me say that I'm not a master mechanic but I am not a novice.

I checked all connections with a meter.

I think my next step is to decide how I'm going to power the fans and create the on off switch.

I think I will use the pwm to trigger the relays on and off and go to the power in to the pwm as power to the fans.

Any other suggestions?

Dano523

If your pwm is fired, then give D3 a call and they will sell you kit to pretty much wire up the fans, and including the needed after marker PWM as well.


Or, just pick up the PWM from them, and you can do the rest of the wiring yourself isntead.

http://www.d3peparts.com/product-p/d3pe-zr1-dualfan.htm