Fans not working dual fans - 2000 Buick Century

Relay Driven Dual Cooling Fan Diagnostics

Hi Julie, the dual fan cooling system generally works with the larger fan being the radiator cooling fan and the smaller fan being the A/C cooling fan! If you start the vehicle and turn on the A/C and select the coldest setting within a few seconds both fans should start working!

Turn the ac on the fans should always come on. if not look in the fuse box for a bad fuse and or a fan relay. then look around the fan area for a finned module this is an electronic fan relay. i think this controls the fan speeds.

Looks like you can get just the motors individually or you can get the fan assembly which comes with the shroud, fans, and motors all preassembled. What kind of warranty do you think you have? 14 years on a factory warranty especially on an electric part seems a little out of the norm.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

There can also be one or more radiator fan relays.Depending on weather you have dual fans or not.

If you can disconnect the wire coming from the fan and connect directly to a 12V source, you will learn if your problem is downstream from there or if your fans are blown, which is unlikely. Check your wiring continuity as far as you can with an Ohm meter.

it helps to tell what a/s system you have, Dual Zone, or not. if the motor has voltage AND ground, it has to work, or its bad. The purple wire is power, the black is ground. If it is Dual Zone, the blower control module regulates blower speed, and could be bad.

2003 Chevy Impala w/dual zone heat/AC. The fan stopped working in speed 1 adn 2. Do I need to replace the switch?

I'm not familiar with your particular car, but this info may be of some help to you...

Dual fan cars work in a few ways:
1) Some only use one fan during normal cooling, and turn on the second either when the temperature reaches a certain level, and/or when the air conditioning is running.
2) Some use both fans for normal cooling, but at least one of the fans have a dual-speed motor. Generally only one has dual-speed motor, which operates at low speed during normal cooling cycles, and operates at high speed at a predetermined temperature, and/or when the air conditioning is running.

Based on this, it's possible that your system is working correctly, or you have the chance that your low speed portion of the cooling system is not functioning. Check the wires going to the fans. If there are only two wires, then it's a single speed fan. If there are three wires, it's a dual speed fan.

Based on that information, you should be able to determine if your system is working correctly or not.

I'm not sure about the sentra, but I know that in my 1998 Eclipse, which has a dual cooling fan, one of the fans is a backup. You might want to make sure of that before you go buying fuses and relays.