Leganza cooling fans

razor · Post by **razor** » Mon Dec 05, 2005 1:03 am

My cooling fans start running soon as I start my engine, and will stay running. Could it be the temp. sensor or would it be in the EMC? Thanks

Post by **PrecisionBoost** » Mon Dec 05, 2005 1:24 am

There are several relays which control the speed and operation of the cooling fans....

In the left side of the engine compartment there should be a fuse and relay compartment

There is a "cooling fan high speed" and "cooling fan low speed" relay

There is also a "cooling fan control relay" located outside the fuse box in the left front of the engine compartment.

These relays get their signal from the ECU which uses two different things to calculate when they should go on.

First is the Coolant Temperature Sensor

Second is the A/C pressure sensor

The ECU will turn on the fan when the A/C is being used.

Unfortunatly the descriptions of the relays aren't very good so you might have to search around a bit to find them.

Hmmmm..... it would appear that the two fans don't work together.... the ECU can turn each one on separately.

The one on the left side of the radiator is the "main cooling fan" and the "aux cooling fan" is on the right side of the radiator

If both are running then it's probably not an issue with the relays.... it's probably an issue with one of the two sensors.