When I turn the AC on, the cooling fan does not turn on and this is preventing the compressor to turn on. I tired powering the fan motor directly with 12v and it runs good. I tested the control module by supplying the input voltage and a PWM signal using an encoder which gave me an output voltage between 0-12v depending on the speed I was turning the encoder. I do not have an oscilloscope to measure the PWM signal from the car but I think the PWM signal is not coming to the control module. what could be causing this?