Engine overheating and fans not working

Hi and thanks for using 2CarPros.com. It sounds like you may have a problem with the fan relays. Here is an overview of what they do. It may seem confusing, but I want you to understand their functions.

Cooling Fan Description and Operation

Cooling Fan Control - Two Fan System

The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block. The fan relay coils receive ignition 1 voltage from the powertrain relay.

During low speed operation, the ECM supplies the ground path for the fan 1 relay through the low speed cooling fan relay control circuit. This energizes the fan 1 relay coil, closes the relay contacts, and supplies battery positive voltage from the fan 1 fuse through the cooling fan motor supply voltage circuit to the right cooling fan. The ground path for the right cooling fan is through the fan 2 relay and the left cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the ECM supplies the ground path for the fan 1 relay through the low speed cooling fan relay control circuit. The ECM grounds the fan 3 relay and the fan 2 relay through the high speed cooling fan relay control circuit. This energizes the fan 2 relay coil, closes the relay contacts, and provides a ground path for the right cooling fan. At the same time the fan 3 relay coil is energized closing the relay contacts and provides battery positive voltage from the fan 2 fuse on the cooling fan motor supply voltage circuit to the left cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

Now, the proper way to check the relays is to use a scanner and prompt them on to see if they send power to the fans. However, chances are you don't have a scanner which can do that. So, here are general directions of how to check a relay.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Here are directions for removal and replacement:

RELAY REPLACEMENT (ATTACHED TO WIRE HARNESS)

REMOVAL PROCEDURE
Locate the relay.
Remove any fasteners which hold the relay in place.
Remove any connector position assurance (CPA) devices or secondary locks.
IMPORTANT: Use care when removing a relay in a wiring harness when the relay is secured by fasteners or tape.
Separate the relay (1) from the wire harness connector (2).

INSTALLATION PROCEDURE
Connect the relay (1) to the wire harness connector (2).
Install any connector position assurance (CPA) devices or secondary locks.
Install the relay using any fasteners or tape that originally held the relay in place.

The relay box on your vehicle is located under the hood in the power distribution box. Open the lid and there will be a list of components and relays. Locate the cooling fan relays and test them.

I hope this helps. Let me know if you have other questions or need additional help.

Take care,
Joe