Attachment 4029Attachment 4028
All you have to do is take the wire from each of the existing oem relays that would go to their coresponding thermo sensor and wire them into the ECU. The ECu is actually a ground for the relay.
The pins on the 98/99 plugs are 17 fan HI, 18 fan low.
So basically on the 1st gen pin 3(blue with black stripe) in A-55 instead goes to pin 18 on the 99 ECU plug and 1st gen pin6 (green with black stripe) in A-55 instead goes to pin 17 on the 99 ECu plug. Make sure pin 1(black) and 4(Blue with yellow stripe) are still plugged in on A-55, only pin 3 and 6 should be re-routed.
If you do it this way you don't even have to remove the thermo sensors. They are electrically removed from the circuit and won't affect anything. Plus if you want to go back to stock it will be an easy retrofit.

