What make , model. Year,. Trucks like big block, 2500 HD 3500 and up have Aux' cooling fan by design. Work harder.
At some point GM added Aux cooling fan to other models to either provide more cooling for radiator, and activated to run to provide more airflow for condenser cooling. A diode is installed to prevent two active power sources. And if it was built with the aux fan it's listed on the RPO tag.
At some point GM added Aux cooling fan to other models to either provide more cooling for radiator, and activated to run to provide more airflow for condenser cooling. A diode is installed to prevent two active power sources. And if it was built with the aux fan it's listed on the RPO tag.