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View Full Version : Wiring gurus? I would like my A/C fan always on

Matej
06-11-2009, 04:53 AM
Is there any way to make the stock radiator fan 'think' that my A/C is on, even though I do not have the climate control unit?

A few years ago my A/C wiring caught on fire, so I removed all of the A/C and heater components, including the climate control, since that entire portion of the interior harness is completely burnt up and unusable.

Recently I have learned that some people who remove their A/C keep the climate control and the fan plugged in, and whenever they want the fan on they just press the A/C button.

I like how it uses the stock connector and relay and everything meant for the fan instead of requiring any extra wiring, but since I cannot use the climate control, is there any way to make it as if my A/C button was on? Do I just need to 'bridge' the fan relay somehow, or is it more complicated than that?

Thanks for any input!
godsmack
06-11-2009, 05:31 AM
the fan has only two wires so hook one up to ground and the other to a switch inside your car leading to either a hot acc wire or directly to the battery.
Matej
06-11-2009, 06:38 AM
That is how I had it setup until now. The old fan was cracked and vibrated a lot, so I recently got a 'new' one from a junkyard in perfect condition. I am just curious in case there is some easy trick to do it before I decide to cut off the connector.
fliprayzin240sx
06-11-2009, 07:44 AM
Wire it up to the AC relay (just not sure exactly how to do it since I dont have a wiring diagram). I know in my S14, when i still had a KA, there was a walkthru in NICO where you can "jump" the AC fan to keep it on all the time when the car is on. I did that and took the clutch fan off and it survived Cali summers like that for 2 years with my AC working fine and engine not overheating.
godsmack
06-11-2009, 07:47 AM
ya you could bridge the wires where the fan relay is and it'll stay on all the time but as for pressing the a/c button you're gonna have to look up the fsm and track it down that way inorder for it to work right. imho it'll be easier with just a switch. especially since you said the wiring was fried.
Mirage
06-11-2009, 10:10 AM
S14? Ground the fan relay trigger wires at the ecu. I think its orange/blue for low speed (relay 1), blue/green for high speed (relay 2), double check the fsm. You could also ground the triggers at the relays themselves. You can throw a switch in the mix so you can control it also.
Matej
06-11-2009, 12:52 PM
Thanks for the tips. This is for an S13, the fan is only one-speed I believe. I will take a look at the relay today.
projectRDM
06-11-2009, 03:54 PM
the fan has only two wires so hook one up to ground and the other to a switch inside your car leading to either a hot acc wire or directly to the battery.

No. This is the shittiest way to do it and will burn even more wiring up.

Ground the trigger wire at the relay, simple. I don't recall the color on an S13, but you'll easily find it, two wire will see power, one will be the fan output. The remaining wire, smaller gauge, is the trigger. Ground it, Fan will come on immediately when the switch is turned on.
Matej
06-18-2009, 03:10 AM
Thank you for the info.

projectRDM, when you say ground the relay wire, do you mean the A/C relay in the driver side relay box, or the condenser fan relay in the passenger side fuse box? I traced the brown wire from the fan connector and it goes to the condenser fan relay.

Here is a picture of the passenger side fuse box cover.
http://www.matejblahut.com/photo/auto/part/acfanrelaybox.jpg

And the condenser fan relay itself.
http://www.matejblahut.com/photo/auto/part/acfanrelay.jpg

Here are few ways I have been thinking about. Please let me know if they are completely dumb and/or would not work.

1. Ground the relay wire as advised, however, I am not sure if this should be done to the A/C relay or the condenser fan relay.
2. Instead of using the relay, just run a wire with spade connectors between 3 and 5, and between 1 and 2, so the circuit is always closed.
3. Cut the ground wire from the fan and ground it even before the connector, and only have the power wire going to the connector.

Would any of those work and make the fan turn on automatically?

Thanks again!
GSXRJJordan
06-18-2009, 04:23 AM
Lol all those options you listed have problems that would stop them from working.

Keep the relay in there - the blue/orange (I think?) wire coming out of the bottom of the relay harness is the one you want to ground. The relay coil gets +12V from the ignition switch, and the ground you provide will have the fan on whenever the ignition is switched on.
kcvpr
06-18-2009, 06:14 AM
Lol all those options you listed have problems that would stop them from working.

Keep the relay in there - the blue/orange (I think?) wire coming out of the bottom of the relay harness is the one you want to ground. The relay coil gets +12V from the ignition switch, and the ground you provide will have the fan on whenever the ignition is switched on.Do you know if the wire would be the same color/ location for an S13?
projectRDM
06-18-2009, 07:33 AM
I don't recall the wire color on an S13, but it's the smaller gauge one (there's two) that doesn't have power when the key is on. Ground it. Done.
tf_90s13
06-18-2009, 09:52 AM
make sure u hit up autozone and get a fuse like u would do for the power wire on an amp for a system. just in case it shorts out it will pop the fuse just in case.
Matej
06-18-2009, 01:45 PM
Ok, so just ground one of the thin wires coming out of the condenser fan relay? I'll see if there's a blue-orange one, I will have to trace which one goes wire.
Thank you for the help everyone.
GSXRJJordan
06-18-2009, 03:12 PM
Ok, so just ground one of the thin wires coming out of the condenser fan relay? I'll see if there's a blue-orange one, I will have to trace which one goes wire.
Thank you for the help everyone.

Yup yup. I want to say the "other" thin wire is either white, or black/red... good luck lol.
Bigsyke
06-18-2009, 08:14 PM
Ive heard that fan isnt designed to be on all the time. I have mine triggered on a toggle switch from the cabin. I grounded cooling fan relay 1.
kcvpr
06-19-2009, 06:05 AM
make sure u hit up autozone and get a fuse like u would do for the power wire on an amp for a system. just in case it shorts out it will pop the fuse just in case.Since the wiring the fan would be running off is all OEM I would assume there would be a fuse already wired in from the factory....????


I don't recall the wire color on an S13, but it's the smaller gauge one (there's two) that doesn't have power when the key is on. Ground it. Done.

And thanks for the help/ advice.
kcvpr
06-19-2009, 07:29 AM
I just mmessed around with this a few minutes ago, and it works perfectly!

The wire that you need to ground on the s13 is the orange wire with blue stripe.
Matej
08-28-2010, 04:49 PM
Hello.
Sorry to bump this thread from over a year ago, however I just did this and it did not work. I just want to confirm if I did it correctly, so I can blame it not working on the goofy wiring in my car.

http://www.matejblahut.com/photo/auto/part/acfanrelay.jpg
The wire I grounded was the wire coming out of #3 on this relay. It was a thin orange wire with a blue stripe.
The other thin wire is #1, which is blue with an orange stripe. Numbers 5 and 2 are the two thicker wires going to the fan connector.

Was #3; the one on the interrupted circuit; the correct wire to ground? Or should I have grounded #1 instead?

Also, when working correctly, should the fan turn on when the key is in the ON position, or when the engine is started? I have only tested it by turning the key to ON, since I cannot start my motor yet.

Thank you for any information once again.




P.S.
To those advising not to have the A/C fan always on, I am not actually using the stock fan. I am only using the connector from it, wired to my electric fans. I just wanted the fan wiring to be neat and plug-and-play, instead of having to use any extra wires or switches.
fliprayzin240sx
08-28-2010, 06:43 PM
It should be #1 or #2 (not sure which way the power is flowing), basically, when that circuit is energized, itll flip the relay switch to connect 3-5. You grounding 3 wont do you any good.

Edit: Reading it again, I say #1 since you said 5 and 2 are thicker wires. Usually, thick wires are positives...
billyy2288
08-30-2010, 04:34 AM
S14? Ground the fan relay trigger wires at the ecu. I think its orange/blue for low speed (relay 1), blue/green for high speed (relay 2), double check the fsm. You could also ground the triggers at the relays themselves. You can throw a switch in the mix so you can control it also.


I also think so.
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