Question for those that have swapped out their radiator fan for an AC one

[GRSHOPR]

OK, so my passenger radiator fan went out, and since I'm planning on using larger turbos in the future, I decided to do what had been advised by others, and swap it out with the slimmer A/C fan, and hotwire them. Did the hotwire, installed the fan, but when I plug it in, it turns on, with or without the key in the ignition. The driver side one works properly, only when the key is to the ON position, but what's up with the passenger side one?? Anyone who has done this mod before got an answer?? Did I miss something? Thanks.

[mb3000]

My guess is that you wired straight to the battery, therefore it will run all the time. You need to connect it to a wire that only gets juice when the key is in the ON position, or while the engine is running at least.

[BaadVR4]

OK, so my passenger radiator fan went out, and since I'm planning on using larger turbos in the future, I decided to do what had been advised by others, and swap it out with the slimmer A/C fan, and hotwire them. Did the hotwire, installed the fan, but when I plug it in, it turns on, with or without the key in the ignition. The driver side one works properly, only when the key is to the ON position, but what's up with the passenger side one?? Anyone who has done this mod before got an answer?? Did I miss something? Thanks.

In the stock configuration, the passenger side fan is "switched" on the ground side while the driver's side is done on the power side. What you need to do is wire a relay into the passenger side wiring. Run an additional fan "ground" side through the relay. Wire the relay operating lugs with the power to close the relay coming from the power side of the driver's fan. That way, the passenger fan will operate just like stock from the temperature sensor, but will also come on anytime you turn the AC on. This way you get the best of both set ups and both fans will run anytime the AC is operating. Really helps with AC when the car is moving less than 35 MPH and you have a big FMIC.

[GRSHOPR]

In the stock configuration, the passenger side fan is "switched" on the ground side while the driver's side is done on the power side. What you need to do is wire a relay into the passenger side wiring. Run an additional fan "ground" side through the relay. Wire the relay operating lugs with the power to close the relay coming from the power side of the driver's fan. That way, the passenger fan will operate just like stock from the temperature sensor, but will also come on anytime you turn the AC on. This way you get the best of both set ups and both fans will run anytime the AC is operating. Really helps with AC when the car is moving less than 35 MPH and you have a big FMIC.

And what if it's hotwired to run all the time?? Just do the relay?? Would that change the wiring configuration?

[GTOJOE]

In the stock configuration, the passenger side fan is "switched" on the ground side while the driver's side is done on the power side. What you need to do is wire a relay into the passenger side wiring. Run an additional fan "ground" side through the relay. Wire the relay operating lugs with the power to close the relay coming from the power side of the driver's fan. That way, the passenger fan will operate just like stock from the temperature sensor, but will also come on anytime you turn the AC on. This way you get the best of both set ups and both fans will run anytime the AC is operating. Really helps with AC when the car is moving less than 35 MPH and you have a big FMIC.

This is correct. Same as what I advised you on the other thread. Hotwired or not the same rules apply. You need another relay.

[BaadVR4]

And what if it's hotwired to run all the time?? Just do the relay?? Would that change the wiring configuration?

When you say "hotwired to run all the time", just how did you do that? The stock wiring has 12V to the passenger side fan without a switch. Just like a wire directly from the battery to the fan. The fan is then turned on and off by a relay that opens and closes the ground wire. The driver's side fan is done the other way around; the relay that turns it on opens and closes the 12V supply. So, if you connect the wiring from both fans together, they would both run constantly, even with the key removed. I, personally, would not run the fans "full time". With the relay set up I described, the fans will be controlled just like Mitsu designed them except when the AC is on and then both fans will run all the time. I have the typical "big" FMIC and Koyo radiator on two cars. Both are 16G turbo set ups and the AC on both work about the same. When it's really hot and humid (triple digits on both) here in middle Georgia, they will hold 25-30 degrees colder than ambient idling at a standstill. I have a dead stock VR4 and it only does about 5-10 degrees better. Now, my wife's 05 Ford Ranger puts out 44 degree air, no matter how hot it gets outside. Of course, it doesn't make 600+ AWHP, either.

Let me know how you did the "hotwire" and I can better tell you what I'd do. LMK. Thanks.

[GTOJOE]

I believe he has had them wired up to run constantly.

[GRSHOPR]

Lol, yeah, I know, Joe. I was just seeing if there was an easier way. I did the standard splicing together on the A/C relay (green with black chaser and black wire). I have a spare relay spot in the under hood fuse box. Think the standard Mitsu relay would be able to hold the power needed to run the fan?? I'll just run the constant power through the relay, and tie the ignition circuit into the activation circuit.

[BaadVR4]

Lol, yeah, I know, Joe. I was just seeing if there was an easier way. I did the standard splicing together on the A/C relay (green with black chaser and black wire). I have a spare relay spot in the under hood fuse box. Think the standard Mitsu relay would be able to hold the power needed to run the fan?? I'll just run the constant power through the relay, and tie the ignition circuit into the activation circuit.

That should work. I standard 30 amp relay (like the one used for fuel pumps) should be just finel

[GRSHOPR]

Hahahaha, or, since they are virtually useless now, what if I rewired one of the High/Low fan relays for the job?