When my third OEM fan went bad, I had had enough. The ONLY problem is that the fan stinks. If I get a fourth, it will go bad too. So, I made my own.
The OEM fan has a high speed relay and a low speed relay. The Saabs have been doing this for over 10 years now. On the Saabs, there was simply a capacitor in-line on the low speed wire until they built it into the fan like on the SSR. So I purchased a 14" Zirgo fan with 2670 CFM and took it apart along with my broken OEM fan and played a little Dr. Frankenstein.
Here's what I did:
1. Remove the old fan motor from the shroud.
2. Take a drill bit or a Dremel and grind out the center hole a little bit to fit the new Zirgo fan motor. The bolt holes do not line-up, so you can line-up one and then just drill 2 new ones in the plastic shroud. I used zip ties to secure the new fan motor to the OEM shroud.
3. Hammer the metal cover off the OEM fan to reveal its circuit board. This is the 2 speed logic. You will see that there are 4 bars that spring on the copper center of the fan, these are the 4 wire contacts for the OEM 2 speed logic. When you remove the logic board you will have the entire round circuit board and the OEM wire harness plug.
4. The black ground wire changes to brown. Follow the brown wire through the contact points on the circuit board until you come to the end of 2 of the 4 wire contacts. These are your 2 ground contacts. The other 2 are your positive contacts. One of the positive contacts runs thru a ceramic capacitor. This is your low speed fan logic. The capacitor is ceramic because it gets very hot. You can carefully remove the square spring loaded contacts keeping only the gold wires to use as wire leads.
5. Jumper the 2 ground leads together. Then jumper the 2 positive contacts together. Connect the ground to the ground line of the new Zirgo fan motor and connect the positive to the positive of the fan motor.
6. Now you have your new Zirgo fan hooked-up to the OEM 2 speed logic. Put electrical tape on your contacts, but do not put tape on the ceramic capacitor - as it will melt the tape and may cause the capacitor to overheat. Zip tie the logic to the shroud.
7. Reinstall your fan and plug the OEM harness back together.
Done.
Mine has worked great all weekend. I let it idle for an hour in the 90 degree Florida sun. The low speed fan was keeping it so cool that I couldn't get the high speed fan to come on. So I took her out and really drove hard. I finally got the high speed to kick in but it only ran for about 30 seconds before it was cool enough to go back to low speed.
It took some time to really customize it. But it's working great now.
This took me awhile to figure out. The 3 wires actually go to 2 grounds and 2 positives on the 2 speed "logic" board. The fan itself is whisper quiet. But if you put your ear to the grill you can actually hear it sucking air thru the radiator. When I let it idle for only 30 minutes, it never went above 205.
But I would not recommend my "surgery" for people that are not mechanically or electrically inclined. You have to sacrifice an old OEM fan and a new aftermarket fan to do it. If you don't know what you’re doing, you may sacrifice more than that.
The OEM fan has a high speed relay and a low speed relay. The Saabs have been doing this for over 10 years now. On the Saabs, there was simply a capacitor in-line on the low speed wire until they built it into the fan like on the SSR. So I purchased a 14" Zirgo fan with 2670 CFM and took it apart along with my broken OEM fan and played a little Dr. Frankenstein.
Here's what I did:
1. Remove the old fan motor from the shroud.
2. Take a drill bit or a Dremel and grind out the center hole a little bit to fit the new Zirgo fan motor. The bolt holes do not line-up, so you can line-up one and then just drill 2 new ones in the plastic shroud. I used zip ties to secure the new fan motor to the OEM shroud.
3. Hammer the metal cover off the OEM fan to reveal its circuit board. This is the 2 speed logic. You will see that there are 4 bars that spring on the copper center of the fan, these are the 4 wire contacts for the OEM 2 speed logic. When you remove the logic board you will have the entire round circuit board and the OEM wire harness plug.
4. The black ground wire changes to brown. Follow the brown wire through the contact points on the circuit board until you come to the end of 2 of the 4 wire contacts. These are your 2 ground contacts. The other 2 are your positive contacts. One of the positive contacts runs thru a ceramic capacitor. This is your low speed fan logic. The capacitor is ceramic because it gets very hot. You can carefully remove the square spring loaded contacts keeping only the gold wires to use as wire leads.
5. Jumper the 2 ground leads together. Then jumper the 2 positive contacts together. Connect the ground to the ground line of the new Zirgo fan motor and connect the positive to the positive of the fan motor.
6. Now you have your new Zirgo fan hooked-up to the OEM 2 speed logic. Put electrical tape on your contacts, but do not put tape on the ceramic capacitor - as it will melt the tape and may cause the capacitor to overheat. Zip tie the logic to the shroud.
7. Reinstall your fan and plug the OEM harness back together.
Done.
Mine has worked great all weekend. I let it idle for an hour in the 90 degree Florida sun. The low speed fan was keeping it so cool that I couldn't get the high speed fan to come on. So I took her out and really drove hard. I finally got the high speed to kick in but it only ran for about 30 seconds before it was cool enough to go back to low speed.
It took some time to really customize it. But it's working great now.
This took me awhile to figure out. The 3 wires actually go to 2 grounds and 2 positives on the 2 speed "logic" board. The fan itself is whisper quiet. But if you put your ear to the grill you can actually hear it sucking air thru the radiator. When I let it idle for only 30 minutes, it never went above 205.
But I would not recommend my "surgery" for people that are not mechanically or electrically inclined. You have to sacrifice an old OEM fan and a new aftermarket fan to do it. If you don't know what you’re doing, you may sacrifice more than that.
