The Cold Case that was NEW on my T when I got it, was one of the biggest P.O.S. fan assys that I have ever seen!
The fans used were: installed as pullers, but wired and bladed for PUSHERS, (yes the air was pushing out the FRONT of the radiator!!!)
Have so many finger guard fins that not much air could get thru, and only blew at 8.3 M.P.H.!!!!!!!!
AND had so much casting flash on both the leading and trailing edges of the blades, AND you couldn't turn the blades around for correct puller operation! And did not come with any instructions!
So I: cut two thirds of the finger guard fins off, detailed the casting flash on the leading and trailing edges of the blades, and made shaft spacers to allow the blades to mount correctly on the motor shafts for pullers without hitting the shroud. Washers will work, but we all know how anal I am.
RESULTS: Wasted 3 hours of my life, and now the fans pull at over 21 M.P.H!!!
Keep in mind that if the car is going faster than the fans can pull, they will restrict the air from going much faster thru the radiator, probably causing overheating with the fans on or off!
Add to that, the finger fins are impeding the airflow, with the fans on or off!
The stock fan has two speeds, with a single speed fan and a resistor, with two feed terminals.
There are a high and low fan relay, so, if you connect each fan to each relay, the issue is it turns off the low speed relay when the hi speed relay is energized, so you still only have one fan or the other operating.
SO, you run a 2 or 3 amp diode from the fan side of the hi speed relay to the switched side of the lo speed relays coil, so it will stay on with the hi speed relay and fan on.
Got that?
TIMINATOR