2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 450Get this manual
ELECTRICAL ('04'05)
COOLANT TEMPERATURE INDICATOR
SYSTEM INSPECTION
Disconnect the engine coolant temperature (ECT) sensor connectorECT SENSOR CONNECTOR
Start the engine and check the indicator If the indicator lights for seconds then goes off, go to next step If the indicator lights and stays on, check for short circuit in the following wire:Yellowblue wire between the ECT sensor and fanignition control module (ICM) connectorsGray wire between the fanICM and indicator connectors If the wires are OK, replace the fanICM