NorCalLt4

I installed my bigger trans cooler and it works great but when i turn on the fan the temp actually starts to climb. Does anyone know why this could be? The thing i find funny is even when the car is off and there is no fluid circulating and i turn the fan on the temp still rises. Could the fan be playing some trick with the guage? Or could the fan really be heating the trans?? Its confusing me so if anyone could help clear this up id appreciate it...
thanks