As soon as I turn the key on, the fan activates and modulates fast and slow

Hello,

The air conditioning plays a role in what speed the fan comes on at. Also when the air conditioning is engaged the fan should come on at high speed, but mainly it is the Electronic Coolant Temperature Sensor (ECT) that sends the signal to Fan Control Module. I have included a description of the operation of the engine cooling fans with a wiring diagram for you in the diagrams down below. Get back to us with what you find out.

Thanks,
Alex
2CarPros

Great information you send me. Very helpfull, thank you.

Hi again amigo, one more question. When the vehicle starts cold, does the fan starts right away or should it wait for temperature to rise and receive the signal? Mine is starting at low immediately you start the engine cold. I read that could be over cooling and would create other problems. Fan clutch looks and feels good. Don't know if when at high rpm's running or climbing it stops or slips and vehicle heats more than normal. Please advice and thanks.
PS. Any testing that can be perform to the fan clutch?

Hello again,

The cooling fan is supposed to be on at low speed all the time to aide in fuel economy. I have included a description of your vehicles engine cooling system as well as a wiring diagram of it in the diagrams down below.

Thanks,
Alex
2CarPros

Thanks, all my question were answered and illustrated great. Appreciate you taking your time to answer. Thanks

Good to hear, please use 2CarPros anytime we are here to help.