Deluxe Cooling Fan mod

[shelbyracing]

Yep

[98aurora]

Thanks!

[shelbyracing]

Ok that switch went bad and made me super irritated. So I rewired the hot wire to the fuel pump relay hot wire and grounded the relay ground wire all the time. So my phones turn on for 3 sec with the fuel pump to let you know they work then Turn on only when car is actually running.

I've had my fans not work before n my motor got rather warm so it's nice to have a check. I had to fly down the road to cool it then turn it off as soon as I parked it.

[1996autobahn]

Hey shelby, so did you run the fans threw a relay or strait threw the $20 dollar module? I'd really like to install the one that I just picked up, but if it burned up with a relay in line then I would rather just take it back. Let me know

[shelbyracing]

Relay man, I was super upset. They shouldn't sell a product unless it's reliable. I thought of maybe reviewing some other ones and putting one on where it will turn on at like 100' only when the car is running.
I think it was from getting wet under the hood. It was connected to the ground relay activation wire.

[1996autobahn]

That's how I want to hook mine up also. Ill try it and make sure that it wont be at risk of getting water in or around it.

So I'm thinking of running it threw the relay as a ground and having the relay serve as the ground for the fans. Then to get power to the fans I can run the fans off of the positive box on the passanger side of the motor.

I think ill mount the $20 box next to the fuse box under the hood and just incase it does fail ill get some fan connections out of the junkyard off of another aurora, so that I can leave the stock hook up there.

I do have a question though, which fan is high speed fan?

[sall]

There are no individual low and high fans. Both fans are low and high speed.

The electric cooling fans are controlled by the PCM. The PCM controls the ground path for the three cooling fan relays. The relays are used to control the high current flow to power the cooling fan motors. Both fans operate together. When minimum cooling is required, the PCM energizes the low speed cooling fan relay #1, and both fans operate at low speed since the fans are connected in series through the series/parallel cooling fan relay #2. When maximum cooling is required, the PCM energizes all three cooling fan relays. The left hand coolant fan is still powered through the low speed cooling fan relay #1, but is now grounded through the series/parallel cooling fan relay #2 and operates at high speed. The right hand coolant fan is powered directly through the high speed cooling fan relay #3 and also operates at high speed.

I would make the new adjustable temp controller ground the OEM relay #1. Not worry about any other wiring and utilize OEM components which are more than satisfactory to handle the load. You would need to use a microrelay or equivalent to switch the adjustable temp controller output to low to ground out relay #1 terminal 86. Don't have time to check my guess work but might later. Just look at schematic on page 1 for cooling fans and description listed above. Bob also posted a simple schematic to just this.

[RCA1186]

Hmm I could swear at low speed I only had one fan running

[bobsblue95]

They are wired (by the three relays) to run in series (voltage gets divided in half) for low speed and parallel (each fan gets 12v) for high speed. I agree with sall, don't bypass the oem relays, use them to do what they are designed to do. Just provide ground to relay #1.

[shelbyracing]

I used OEM and uncooked it from computer. I have high speed plugged in low speed plug. Then used the low speed relay near coils. (same one listen for the clicking one when u ground it.

[sall]

Sept 8, 2012 9:50:39 GMT -6 RCA1186 said:

Hmm I could swear at low speed I only had one fan running

Flip your AC on and check. If only one is working there is a problem.

[RCA1186]

I remember one was on at low speed for low and at high they were both on moving faster (old aurora not current)what would cause that if its not supposed to be that way?

[bobsblue95]

I'd have to study the schematic to see if that's even possible, but it seems like in low speed if one fan isn't working it's either a bad fan motor or a bad relay. A bad motor would also not work in high speed, plus it would prevent the other motor from getting any current since they are in series. If it's a relay problem, I would expect the single fan to be running at high speed. This is all theoretical though. Again, I'd have to study the schematic.

[mikeaurora]

Apr 6, 2012 17:53:26 GMT -6 sall said:

Good stuff! Should be a little different on '96-'99 PCM though, but same idea can be used.

I know this is an old thread, but I have a second gen aurora (2001, 4.0) with 133,000 miles and want to figure out some way to get more fan involvement in controlling engine temp-my wife uses this as her commuter and it will go above 224 degrees on the way home most warm days. I have a new radiator, new 18 lb cap, new 180 degree thermostat and the water pump has less than 8,000 miles on it. It has not overheated, and the cooling system does hold pressure when hot. If the ac is not on, the fan does not run until it gets to 224 (i have a ultra gauge installed so i can see actual temps). When the AC is running, the fans do run, and they will go up to high speed when over 228. I have noticed that this car will run around 200 degrees on a very hot day if the hood is open and have looked for any way to cool the engine compartment when the hood is closed-the air dam and all the original underhood parts are still there and in place. I know these generally run kind of hot, but I cannot see how 224 is good for it, especially in stop and go city driving. Has anyone with a second generation done this fan mod, and what wires did you tap/change to get the low and high speed fans to run? I do not want to get rid of this car, it is still quiet, fast and beautiful. I have always maintained it and it gets full synthetic at less than 3000 mile intervals, and I only fill it with premium 93 octane. It runs smooth as glass, and handles great still. She is driving my 2000 Intrigue until I can solve this-what I'd like to do is just what is described here, low speed fan always runs and high speed goes on when the low is supposed to-

anyone know what color wires I need to work with, and where the best place to tap these might be? Thanks

[mikeaurora]

Must not be a lot of readers on this forum, I have done some research and was surprised to see on a friends' Mitchell account that second generation cars are supposed to turn on the fans at 222, and high speeds doesnt kick in until 228-just seems too hot to me. This thread only has color wire location and description for the first gens. Id like to do this exact mod, or find a source to send the ECU to get the computer flashed to change temp control for the fans. Anybody?

[awehlage]

Hasn't been done on a 2G yet AFAIK. Just need someone to take the time with some schematics and DMM to do some research.

You can get a tune to change the cooling fan temp triggers.

[RCA1186]

Jul 25, 2014 0:36:32 GMT -6 mikeaurora said:

Must not be a lot of readers on this forum, I have done some research and was surprised to see on a friends' Mitchell account that second generation cars are supposed to turn on the fans at 222, and high speeds doesnt kick in until 228-just seems too hot to me. This thread only has color wire location and description for the first gens. Id like to do this exact mod, or find a source to send the ECU to get the computer flashed to change temp control for the fans. Anybody?

madtuner.com/


or PM him, check out this thread

[awehlage]

Looked at the PCM schematics for the 2G. I believe if you ground the DK GRN wire (low speed fan relay) you will get low speed fans on all the time. Need to find how to get that with ignition only as the relays receive constant +12v.

Could be as simple as adding a SPDT relay triggered by a switching (ignition) voltage source.

Pin 85 - Ground
Pin 86 - +12v (IGN)
Pin 30 - Low speed fan control wire (DK GRN) PCM side
Pin 87 - Low speed fan control wire (DK GRN) Low speed fan relay side

[sunco2]

I just unhooked coolant level sensor and the fans run on high all the time, now my 99 aurora runs cool. Just hook it up for cooler weather. when warning light comes on just press button on display once and warning is gone. I love my car but will not spend extra on it.

[sall]

May 4, 2017 20:37:22 GMT -6 sunco2 said:

I just unhooked coolant level sensor and the fans run on high all the time, now my 99 aurora runs cool. Just hook it up for cooler weather. when warning light comes on just press button on display once and warning is gone. I love my car but will not spend extra on it.

Disconnection of the coolant level sensor results in low speed operation. If you need to have them on all the time you have cooling system issues.

[RCA1186]

Disconnecting the sensor also adds the possibility that one day you actually WILL have low coolant and not know about it until you start to overheat