Removing the fan control module from my MK1 pick-up where the previous owner had kept it as a part of the Motronic MK3 harness.

It’s an accepted wisdom that it is easier to purchase someone else’s done or mostly done project than it is to start with a clean slate. If nothing else it will at least be cheaper. That does, however, mean that you’ll stumble onto items that just won’t work for you; like a fan control module. 

VW 3A0919506 Fan Control Module

I’ve decided to remove the fan control module (OEM part# 3A0919506) that came as a part of the 1996 VW Jetta wiring harness that the previous owner used which makes this a CE2 setup. The car doesn’t have AC and I can’t see myself going through the trouble of adding it. Space is limited and I don’t need to add another source of heat in the bay.

I’ve decided to just wire up the coolant fan thermo switch (OEM part# 191959481A) outputs; red white, and red yellow wired to a 30 amp SPST relay that will sit in the auxiliary relay and fuse box I purchase for the headlights. Power for the fan will run through a 10 AWG wire from the battery positive terminal and through a 30 amp fuse to the relay and straight to the fan from there.  Ground that and the relay back out to the battery. The thermo switch itself will pull power straight from the battery with a 5 amp fuse as a precaution.  I’ll run that circuit off of the same relay/fuse box mentioned above.

So to recap:

  • Battery positive to thermo switch via the red 14 AWG wire with a 5 amp fuse
  • Thermo as the trigger through pins 85/86, red yellow & red white wires. 86 to ground
  • Battery positive to pin 30 on the relay via 10 AWG red wire with a 30 amp fuse
  • Relay pin 87 to fan motor positive via 10 AWG red wire
  • Fan motor ground back to the wire coming off of pin 86 and to battery negative

Wiring diagram to use a 30 amp relay to replace the MK3 fan control module

Need to do some research if I can find a thermo switch that triggers at a lower temperature than the OEM setting.