radiator fan wiring

949 · 10-20-2005, 05:30 AM

does anyone have the wire coding for the radiator fan on the o4 impreza's?
i believe there are 4 or 3 wires comming out of the fan motor and then into a plug which seems to only have 3 wires but not sure. i can only assume ground, power, but i dont know what the third would be for? and what is the color code for the individuals comming out of the fan motor?

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3barboost · 10-12-2006, 04:58 PM

free bump as I would like to know as well as I have ditched my oem fans with 3 wires for aftermarket fans with only two wires !!!
the oem wires are 3 - yellow/red - white/red and black
which is max speed ? or is it not a speed differential setup

zaarin · 12-06-2006, 12:11 AM

I have an 02 WRX, but I imagine the wiring is the same in 04/05. (If I'm wrong, call me out!)

Anyway, on my 02, there are actually four wires coming out of the fan motor itself(!). Yellow, Blue, Green, and Black. These go to a plug, and out of the other side (opposite the fan itself) of the plug come only three wires.

On both fans, one of the three is black. The black wire should be ground (if I remember right). Both of the other two are power. I don't know why, but both fan motors have two power lines and only one ground.

Each motor has two relays. Both main fan motor relays draw share one power source, and both sub fan motors draw power from another power source. However, main relay 1 and sub relay 1 share a ground through the ECM, and main relay 2 and sub relay 2 share a separate ground through the ECM.

Since the circuit is ground side controlled by the ECM, I think the reason for having two power inputs and two grounds is so that the ECM can control one or both fans coming on under different conditions. Maybe that's how they get the fans to both always turn on with the AC. I'm trying to figure this out right now because I believe I have a motor with high amp draw, but I can't figure out which of the two it is and I don't have an amp-o-meter thingie.

949 · 12-14-2006, 11:41 AM

thanks for the info, do you have pics?

can anyone else back this up? i dont want to fry anything.

zaarin · 12-16-2006, 01:51 AM

No pics unfortunately, but the wires and the connectors are easy to see, just open the hood up and peek down in there. The connectors are hanging out at the bottom corners of the radiator. They should stand out by the colors I mentioned above, and because of the fact that there are different numbers of wires coming out each side of the connection.

10-20-2005, 05:30 AM	#1
949 Scooby Specialist Member#: 58906 Join Date: Apr 2004	radiator fan wiring does anyone have the wire coding for the radiator fan on the o4 impreza's? i believe there are 4 or 3 wires comming out of the fan motor and then into a plug which seems to only have 3 wires but not sure. i can only assume ground, power, but i dont know what the third would be for? and what is the color code for the individuals comming out of the fan motor? * Registered users of the site do not see these ads.

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10-12-2006, 04:58 PM	#2
3barboost Scooby Newbie Member#: 73609 Join Date: Nov 2004 Chapter/Region: International Location: Johannesburg South Africa Vehicle: 2002 wrx White	free bump as I would like to know as well as I have ditched my oem fans with 3 wires for aftermarket fans with only two wires !!! the oem wires are 3 - yellow/red - white/red and black which is max speed ? or is it not a speed differential setup

12-06-2006, 12:11 AM	#3
zaarin Scooby Specialist Member#: 95404 Join Date: Sep 2005 Chapter/Region: SCIC Location: 118/210 Vehicle: 2002 WRX Wagon What color is bird crap?	I have an 02 WRX, but I imagine the wiring is the same in 04/05. (If I'm wrong, call me out!) Anyway, on my 02, there are actually four wires coming out of the fan motor itself(!). Yellow, Blue, Green, and Black. These go to a plug, and out of the other side (opposite the fan itself) of the plug come only three wires. On both fans, one of the three is black. The black wire should be ground (if I remember right). Both of the other two are power. I don't know why, but both fan motors have two power lines and only one ground. Each motor has two relays. Both main fan motor relays draw share one power source, and both sub fan motors draw power from another power source. However, main relay 1 and sub relay 1 share a ground through the ECM, and main relay 2 and sub relay 2 share a separate ground through the ECM. Since the circuit is ground side controlled by the ECM, I think the reason for having two power inputs and two grounds is so that the ECM can control one or both fans coming on under different conditions. Maybe that's how they get the fans to both always turn on with the AC. I'm trying to figure this out right now because I believe I have a motor with high amp draw, but I can't figure out which of the two it is and I don't have an amp-o-meter thingie.

12-14-2006, 11:41 AM	#4
949 Scooby Specialist Member#: 58906 Join Date: Apr 2004	thanks for the info, do you have pics? can anyone else back this up? i dont want to fry anything.

12-16-2006, 01:51 AM	#5
zaarin Scooby Specialist Member#: 95404 Join Date: Sep 2005 Chapter/Region: SCIC Location: 118/210 Vehicle: 2002 WRX Wagon What color is bird crap?	No pics unfortunately, but the wires and the connectors are easy to see, just open the hood up and peek down in there. The connectors are hanging out at the bottom corners of the radiator. They should stand out by the colors I mentioned above, and because of the fact that there are different numbers of wires coming out each side of the connection.