Repurposing MKV fans Need to understand wiring

I am re-purposing a set of MKV fans. There are 2 heavy leads that provide ground and power. There are also a small purple/yellow and blue lead that are required to make the fans run. Before I let the magic smoke out, how do these small leads tell the fans to run?


Just hooking hot and ground is not enough to make them run.


Thanks

i'm pretty sure it's a PWM signal from the ecm..you would have to reverse engineer the signal somehow maybe using an arduino. In your shoes i would go for a dumb fan setup.

Yep, there is a processor in the left fan, that requires a signal from the ECU to tell it to run. It then in turn outputs the proper voltage to the motor, as well as out to the right fan. You cannot just power it up.

got a couple mk4 beetles from a farmer with the fans on a switch
from the rats nest mess of where the fan control module was torn out I'm pretty sure he couldn't have figured out much of anything wiring wise beyond stabbing the little wire with 12v
try just giving it 12v

[486] said:

got a couple mk4 beetles from a farmer with the fans on a switch
from the rats nest mess of where the fan control module was torn out I'm pretty sure he couldn't have figured out much of anything wiring wise beyond stabbing the little wire with 12v
try just giving it 12v

Click to expand...

the mk5 fans, which the OP is referring to, will fry if you put 12v to the small wire... my buddy tried this and cooked a set. These are a different ball game with the built in controller that requires a special signal from the ecm

oh jeez
My eyes cross funny when trying to read roman numerals
it all looks like mk4 to me, lol