themixtoo Posted February 14, 2016 Share Posted February 14, 2016 (edited) Since I had to lower the Legacy radiator in the Brat chassis and the EJ22 engine is only 4 inches from the core support, I had to eliminate the factory fans from the back of the radiator. I purchased three 8 inch pusher fans and have installed them in front of the radiator,but still behind the grill. The factory electrical connection has three terminals (one black, one blue and one green wire). The pusher fans only have two wires (one black and one blue wire). How should I wire this up? Has anyone else run into this problem before? Thanks, Edited February 14, 2016 by themixtoo Link to comment Share on other sites More sharing options...
Numbchux Posted February 14, 2016 Share Posted February 14, 2016 Well, if it's got an EJ engine, ECU, and radiator, it doesn't really matter what the pins on the stock plug did, as they probably aren't attached to anything anyway (I think the stock fan was controlled by a simple thermoswitch, but that was in the radiator end tank. EA82 for sure). EJ ECU has 2 fan relay control wires, they are grounded to activate a relay, which would supply power to the fan. One wire on the fan needs to be grounded, and the other gets power. Reversing those makes the fan spin the other way. The better ones have a curved blade that has to be flipped on the motor to be most efficient. If I were actually wiring 3 fans up, I'd probably put one on the main control, and 2 on the sub control. Although, I rarely even needed one fan (literally....I think I put more miles on my loyale without a functioning fan than with)! Alternatively, there are universal fan control units, but I've used a couple of those with mediocre long-term reliability. Or you could use a switch (or 2....or 3) to control a relay(s). Link to comment Share on other sites More sharing options...
themixtoo Posted February 14, 2016 Author Share Posted February 14, 2016 Thanks for the info...I am using the complete EJ wiring harness and I have the wiring diagram, but it appears that the blue wire and the green wire are both 'hot'. I planned to split the fans, two to one plug and one to the other plug. The thermo sensor on the EJ system is not in the radiator, its on the engine. Do you think I can just eliminate one of them? Link to comment Share on other sites More sharing options...
Numbchux Posted February 15, 2016 Share Posted February 15, 2016 Oh, you've run the FULL EJ harness, out to the fan plug. What year and model is your EJ donor, and I'll look at the diagrams. I've never done it that way... You are exactly correct. The EJ fans are controlled by the ECU, which uses a temp sensor in the coolant bridge. I was thinking you were talking about plugging the fans into the EA81 harness, which would have used a switch on the radiator. Link to comment Share on other sites More sharing options...
themixtoo Posted February 15, 2016 Author Share Posted February 15, 2016 (edited) Thanks for your help. I have installed everything from my '95 Impreza Outback donor car with OBDII.... combo meter, steering column, front suspension, rear suspension, all except the heater box and the HVAC controls. Edited February 15, 2016 by themixtoo Link to comment Share on other sites More sharing options...
Numbchux Posted February 15, 2016 Share Posted February 15, 2016 Right....now I remember why I don't mess with that convoluted nonsense. ASSuming your donor EJ had A/C (I haven't seen one without, but theoretically they exist), it has 4 relays. Stock fans are 2 speed. 3 Pin connectors, Black is ground on pin 1 on both of them. Main control on the ECU, activates the fan relay in the fuse box, and one in the A/C relay holder (IIRC, 2 fuses and 4 relays right next to the fuse box) giving 12v to pin 3 on both fans (Yellow with Red stripe on main fain, White with Blue stripe on Sub fan). Secondary ECU control activates the other 2 relays in the A/C holder, which gives 12v to the pin 2 on both fans as well (Light Green with Black stripe on main fan, and Yellow with Green stripe on sub fan), kicking them into high speed. So yea, I'd probably use the low speed wire (as it comes on first) from one of the fans to a single fan, with the best airflow. And then use each of the high speed wires to power your other 2 fans. 1 Link to comment Share on other sites More sharing options...
themixtoo Posted February 16, 2016 Author Share Posted February 16, 2016 Thank you very much. I will try just what you suggest. Link to comment Share on other sites More sharing options...
themixtoo Posted February 16, 2016 Author Share Posted February 16, 2016 What I forgot to mention was that I had to eliminate the AC compressor due to a lack of room for installing the coolant tank reservoir. I had hoped that I could eliminate the AC circuit and use it for the power window circuit that the Brat had but the Impreza didn't have. Do you think I could eliminate 2 of the 4 relays you mentioned? Link to comment Share on other sites More sharing options...
pontoontodd Posted February 18, 2016 Share Posted February 18, 2016 Right....now I remember why I don't mess with that convoluted nonsense. ASSuming your donor EJ had A/C (I haven't seen one without, but theoretically they exist), it has 4 relays. Stock fans are 2 speed. 3 Pin connectors, Black is ground on pin 1 on both of them. Main control on the ECU, activates the fan relay in the fuse box, and one in the A/C relay holder (IIRC, 2 fuses and 4 relays right next to the fuse box) giving 12v to pin 3 on both fans (Yellow with Red stripe on main fain, White with Blue stripe on Sub fan). Secondary ECU control activates the other 2 relays in the A/C holder, which gives 12v to the pin 2 on both fans as well (Light Green with Black stripe on main fan, and Yellow with Green stripe on sub fan), kicking them into high speed. So yea, I'd probably use the low speed wire (as it comes on first) from one of the fans to a single fan, with the best airflow. And then use each of the high speed wires to power your other 2 fans. Thanks for this info, makes sense now that I look at the fans, wiring, and wiring diagram. So it seems from testing them and looking at the diagram that both hot leads need power for high speed, the black one is ground as you say. I've had issues with at least one pin on the fan connector failing and overheating when running hard. When it ran hot it looked like the fans may have just been running at low speed once I got them both working. Can I just wire both + leads for both fans to a switch on the dash as an override? I'm thinking straight from the battery to a 30 or 40A fuse, to the switch, back to all four fan wires. Or is there a good fused lead I should splice into? This would run both fans on high regardless of some sort of sensor/ECU malfunction, relay failure, or another fan connector gone bad. But they will still come on and off normally with the switch off. Link to comment Share on other sites More sharing options...
Numbchux Posted February 18, 2016 Share Posted February 18, 2016 (edited) Thanks for this info, makes sense now that I look at the fans, wiring, and wiring diagram. So it seems from testing them and looking at the diagram that both hot leads need power for high speed, the black one is ground as you say. I've had issues with at least one pin on the fan connector failing and overheating when running hard. When it ran hot it looked like the fans may have just been running at low speed once I got them both working. Can I just wire both + leads for both fans to a switch on the dash as an override? I'm thinking straight from the battery to a 30 or 40A fuse, to the switch, back to all four fan wires. Or is there a good fused lead I should splice into? This would run both fans on high regardless of some sort of sensor/ECU malfunction, relay failure, or another fan connector gone bad. But they will still come on and off normally with the switch off. You could do it that way. The way I would do it, would be to splice into the 2 wires at the ECU, and run them to a Double Pole (this would keep the 2 circuits separate when the switch is off) switch to ground. That way there's no load on the switch, and you're maintaining stock fuse and relay functionality. That does not protect against relay failure, but with 4 relays, the system is already pretty redundant. What I forgot to mention was that I had to eliminate the AC compressor due to a lack of room for installing the coolant tank reservoir. I had hoped that I could eliminate the AC circuit and use it for the power window circuit that the Brat had but the Impreza didn't have. Do you think I could eliminate 2 of the 4 relays you mentioned? The way I mentioned wiring it, would use 3 of the 4 relays to control your 3 fans. So you could possibly re purpose one of them, there is another relay on that holder that is for the A/C compressor, that you obviously won't be using. Edited February 18, 2016 by Numbchux Link to comment Share on other sites More sharing options...
themixtoo Posted February 18, 2016 Author Share Posted February 18, 2016 Thanks again..... I'm looking at the Power supply Routing Wiring Diagram and in the 'Fuse/Relay Location' picture, which relay is the AC Compressor relay? I'm sorry to ask these stupid questions, but some of this is 'Greek' to this old man. Link to comment Share on other sites More sharing options...
pontoontodd Posted February 19, 2016 Share Posted February 19, 2016 Thanks again..... I'm looking at the Power supply Routing Wiring Diagram and in the 'Fuse/Relay Location' picture, which relay is the AC Compressor relay? I'm sorry to ask these stupid questions, but some of this is 'Greek' to this old man. This is judging by wire colors, you might want to unplug the relay and use a probe to verify. There is a row of four relays and a pair of relays. It is the last one in the row of four closest to the pair. It is labeled AC #4 on the fuse box cover. Link to comment Share on other sites More sharing options...
themixtoo Posted February 19, 2016 Author Share Posted February 19, 2016 Great, Thank you very much. Link to comment Share on other sites More sharing options...
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