Saturday I was driving my car and noticed that the transmission temperature was at 185*. It usually runs 150*-165* even on hot days cruising through the park at 35 mph. It has a Derale trans cooler with a fan and shroud mounted to the cooler. I get out of the car and can hear the trans cooler fan running. As I stand in front of the car, I can feel the hot air blowing through the grill. I've put 4200 miles on my car and the fan functioned normally. I assumed that it must be the relay shorted, but it's fine. The fan has a blue (+) and a black (-), which is what the instructions say and that's how it's wired. If I put + to the black wire and - to the blue wire, the fan runs correctly. I find it hard to believe that the motor has been running backwards for the last three years because the trans temperature has never gone that high and we had a lot of hot weather the last two years. Is it even possible for a motor to turn the opposite direction on its own? I did have a Fiero at work back in the 80's that the fan turned the wrong direction, but it was a new car and a replacement motor fixed that.
The only possible way for a DC motor to turn the wrong direction is for the Polarity to have been changed . I.E. positive is on ground and negative is on + battery
Or someone hooked the battery up backwards making Positive the ground . I've seen tire stores do it before . Engine will still start and run .
When I swapped the wires at the fan motor, it made the wiring from the relay incorrect and it also made my manual fan switch in the dash positive instead of negative and the thermal switch now on the positive side instead of the negative side. I ordered a Derale replacement motor from Summit. When I received the motor, I read the instructions (yeah, I know, hard to believe!) and the said that the motor is reversible, just swap the pos and neg wires AND TURN THE FAN BLADE OVER. As it turns out, after I pushed the radiator back far enough to get my hand in behind the trans cooler, it had some airflow on the back side of the cooler, but the air flow didn't seem much different in either direction. I removed the fan blade and flipped it over and now the puller fan works great. The fan was just put on in the pusher direction instead of the puller direction. I guess that you have to check everything before installing on the vehicle. If it doesn't rain tomorrow, I'll drive it and monitor trans temperature.
Turning the fan blade over will not change the direction of air movement (reversing the motor does that), bit it WILL make it a lot more efficient. I can tell of new reverse running fans from work, POOR QUALITY CONTROL. Bruce Roe
