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AC Fan Wiring

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FWD98GST

20+ Year Contributor
149
0
Apr 6, 2003
San Diego, California
Here's the deal... I hooked up a 11" spal fan for the AC. I noticed that there is one live wire which is a blue one and the ground is black... First of all, is there a high or low setting for the AC fan? My setup for the fan seems to be low and doesn't really blow really hard... I have two other blue wires that I didn't connect... Should I be utilizing those two blue wires at all to make the fan go faster? Or this is it.. It's just a one speed setting for the AC fan?

Thanks..
 
After looking at the wire diagram for the AC fan the high speed fan wire is a blue-white wire the solid blue wire is the low speed wire. Black is of course ground and so is the blue-black one.
 
yah man.. I know that 11" spal fan can blow air harder than what it is set at right now.. So i'll go re-check the wires and set it up for high speed, according to your information..

Thanks man for your help :thumb:
 
Staytuned said:
After looking at the wire diagram for the AC fan the high speed fan wire is a blue-white wire the solid blue wire is the low speed wire. Black is of course ground and so is the blue-black one.
Just to clarify..... If I only hook uo the blue-white wire and the black ground, my fan will work fine?? I wont need to do anything w/ the other two wires, right?
 
OK, so what about the other fan (driver's side fan). The wire colors are a little different.... There appears to be a black, a blue, a white, and a white-blue. I wamt to run the fan on high only. Which wires are the high speed power and ground?
 

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Ok hold the phone...today I go out and start up the car and let it run. I hit the AC button thinking the fans would come on like they have been doing before and I get nothing. So I plug the AC relay back in thinking they might come on this time ...still nothing. So I go on to something else for awhile and let the car heat up alittle more. I then hit the AC button with the relay plugged in and whamm they come like they are supposed to. But then they both shut off as the AC compressor cycles off.

I am going to try to wire them slightly different than I have them now to see if I can change it. I am going to hook all the grounds to the grounds on the fans and all the low and high speed wires to the positive on the fans.

This is how I have it now and I am having in consistant results.

AC side high speed wire to positive on fan. I left the low speed wire unconnected.
AC side ground black wire to ground on fan. I left the Blue-black (ground also) wire unconnected

RAD side high and low speed wires together to positive wire on fan.
RAD side black ground wire to ground wire on fan. I left the Blue-green (ground also) unconnected.
 
Guys, on the radiator fan there three speeds....the stock fan motors are stepper motors and on 2G's you'll find three speed settings (I believe its just LO and HI on 1G's)
The relays are all triggered when the car reaches certain temps and if AC is on or off. Also, if the car is cold and you kick on the AC don't expect the fans to kick in until the car reaches proper water temp.

Radiator
LO1
LO2
HI

Condensor
LO Operates under hot conditions (no AC)
HI Operates under hot conditions w/ AC ON

I don't think connecting the LO1, LO2 and HI outputs to the positive (+) on a aftermarket fan....nor the LO and HI outputs to a positive (+) is a good idea. I could be wrong but I think you run the risk of destroying your fan relays and screwing up the electrical. I understand the logic behind it, but would advise against it. Maybe someone with more electrical background can comment on this since I only play electrcian on the weekends.

Radiator
Pin1 White/Black - LO1
Pin2 Black - GROUND
Pin3 White/Blue - HI
Pin4 Blue/Green - LO2

Condensor
Pin1 Blue - LO
Pin2 Black - GROUND
Pin3 Blue/White - HI
Pin4 Blue/Black - GROUND
 
Ok if I wire it to run on high only then I should be alright then. Because then the fans would come on when engine is hot right? But why would my fans shut off when the AC compressor cycled off? Do they switch to low speed when the AC compressor cycles off? My stock fans never stopped when my AC was on before.
 
I looked up the condenser fan wiring diagram last night, and it appears that
the stock fan runs at two different speeds. When the A/C is turned on, the
fan is turned on at a low speed; when the second fan kicks in for cooling
the radiator, both fans are run at a high speed (the second fan only runs at
the one speed). The four connectors, then, consist of two ground
connections and two power connections; and each pair is connected to a
single relay ("high-speed" relay or "low-speed" relay).

If you're replacing the stock fan (4-terminal connector) with a 2-terminal
replacement fan, you'll need to make some *very minor* wiring changes. The
new fan will only run at one speed ("no Hi/Lo for you!"), but that shouldn't
matter. Here's how to do it (connector reference at bottom):

First, check the wiring harness for correct function:

Turn on your car (make sure it's cold), make sure your A/C button is on, and
turn the blower switch to something other than "off." Unplug the connector
from your old fan (connector A-39) and attach a voltmeter between pins 1 &
either 2 or 4 on the engine side of the connector (negative to pin 2 or 4;
positive to pin 1). You should see +12V (approximately). Turn off your A/C
(hit the button), remove the voltmeter and stash the wires where they won't
catch or drag while driving, then go for a spirited drive on a hot
afternoon. You need to get the car hot enough that the radiator fan (the
one on the passenger's side) turns on. Stop the car (not in traffic), pop
the hood, and check to make sure that when the radiator fan turns on, you
see ~12V between pins 3 and either 2 or 4. If any of this does not check
out, you may need to replace the dedicated fuse (20A) or one of the two
condenser fan relays (depending on which one was not working). I'm not
going to cover that here.


Now, figure out which wire should be "hot" (postive voltage relative to the
other) in order to turn your new fan so that air is drawn *into* the engine
bay. Connect this to pins 1 & 3; connect the remaining wire from your fan
to pins 2 and/or 4.

Testing:

Turn on your car (make sure it's cold), make sure your A/C button is on, and
turn the blower switch to something other than "off." Your 2-wire fan
should now turn on. Turn off your A/C (hit the button) and go for a
spirited drive on a hot afternoon. You need to get the car hot enough that
the radiator fan (the one on the passenger's side) turns on. Stop the car
(not in traffic), pop the hood, and check to make sure that when the
radiator fan turns on, the A/C fan turns on as well. If all is well, your
work is done. If not, check to make sure you have performed each step
correctly.

===========================

Connector (A-39) reference:
(Double outline indicates MALE connector. If you can't tell which one is
the MALE connector, put down your tools, walk slowly away from the car, and
sell it as soon as possible because you're not worthy... Seriously, it's
the one with the pins sticking out.)

=====+===== (one prong sticking out)
|| 1 | 2 ||
||===+===||
|| 3 | 4 ||
===+===+=== (two prongs sticking out)
 
Staytuned said:
Ok if I wire it to run on high only then I should be alright then. Because then the fans would come on when engine is hot right? But why would my fans shut off when the AC compressor cycled off? Do they switch to low speed when the AC compressor cycles off? My stock fans never stopped when my AC was on before.

Yes, you can wire both HI relays (Radiator and Condensor fans), the only problem is that they will only activate at higher engine temps....therefore your car will have to run HOT before they kick on.

I suppose you can get away with wiring the HI relay wire on the Condensor fan provided you run your stock radiator fan since the stocker will work still work w/ LO1, LO2 and HI.

I saw that on NABR as well.

At the time I actually thought of wiring together the LO1, LO2 and HI to the positive Fan wire as well but was afraid of electrical issues or potentially frying relays(as I stated above) Basically, I was to lazy to look into it further. But I still think its worth looking into. I asked the same question not to long ago but never got feedback from anyone.

At any rate, what I ended up doing was wiring only the HI relays on my aftermarket fans. But I control them via DSMLink. There's an option in DSMLink that allows you to keep both fans running all the time. Since my car runs hot and I only drive my car in the SUMMER(provided its running) it worked out.

You can also get a thermostat and w/ probe that sits in the radiator which will kick the fans on and off depending on what you set the temp at. Hope that helps.
 
Screw it to avoid problems with my relays I am going to wire the fans on low speed.
Thats wiring both grounds on the AC side to the ground on the AC fan and both grounds on the rad side to the ground on the rad fan. And wire the solid blue wire on the AC side to the positive on AC fan. And wire the white-black wire to the positive on the rad side.
 
Staytuned said:
Screw it to avoid problems with my relays I am going to wire the fans on low speed.
Thats wiring both grounds on the AC side to the ground on the AC fan and both grounds on the rad side to the ground on the rad fan. And wire the solid blue wire on the AC side to the positive on AC fan. And wire the white-black wire to the positive on the rad side.

Not a good idea, because as soon as the ECU turns on the HIGH RELAYS it will turn off your lows. So when you need your fans on the most, they'll be off.
 
Thats OK I have never gone over 210F in my car and highs don't kick in till 242F. Plus I usually use my AC button as a backup to turn the AC and rad fans on. This works when I pull the AC relay out.
 
I thought you might be able to do it like that but I am concerned with this lo1 lo2 and hi relays that the rad circuitry has and I am concerned with how my AC fans will work. So I am going to only use the low relays for now.

I have tested what relays come on and when they do....and I have seen only my lows used. At around 210F the rad fan comes on and is powered by the low speed rad relay. I switch on my AC and both fans come on using the low speed relays. So for now I am only going to use them and see how that works.
 
Staytuned said:
I thought you might be able to do it like that but I am concerned with this lo1 lo2 and hi relays that the rad circuitry has and I am concerned with how my AC fans will work. So I am going to only use the low relays for now.

I have tested what relays come on and when they do....and I have seen only my lows used. At around 210F the rad fan comes on and is powered by the low speed rad relay. I switch on my AC and both fans come on using the low speed relays. So for now I am only going to use them and see how that works.
So at what point does each one come on and go off (between LO1, LO2, and HI)??

Radiator
Pin1 White/Black - LO1
Pin2 Black - GROUND
Pin3 White/Blue - HI
Pin4 Blue/Green - LO2
 
Why not just setup a relay block? 3 relays each triggered by the one of the inputs (LO1, LO2, and HI) The fan is then powered by a fuse protected wire from the battery. That way you protect the existing relays and the car will activate the fan as it used to.

That said, I have not done so and have LO1 and ground tied together for the last 6 months.. with no problems. I'll check it out though. I figured the high and lo each had their own ground.
 
With the AC button off the rad fan comes on at these temps: This is for 5 speed turbo 2.0l.

at 28 mph or less and temps below 203F all fans are off.
at 203F-210F rad fan comes on medium (didn't for me. only low did)
at 210F or more rad fan come on high and AC fan comes on medium? (thats a headscratcher)

At 28-50 mph and temps lower than 194f all fans are off.
at 194F-210F rad fan comes on medium.
at 210 or more rad fan comes on high and AC fan comes on medium.

At 50 or more mph and temps 210F or less all fans are off.
at 210F or more rad fan on high and AC fan on medium.

Now with AC button on.

At 12mph or less and temps at 210F or below both fans are medium (again only low speed relays came on for me)
at 210F - 242F both fans are are on high.
Same for all other speeds.


After reading 500 posts last night on fans and wiring I have decided to wire them all together. The way it looks is all the different speeds have their own relay so there shouldn't be a problem.....I hope.
 
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