If the fan works with direct voltage applied, the motor is ok so you need to check if it is the fan relay or switch.
Check the thermosensor switch wire for proper connection. If connections are ok, disconnect and bridge them with a jumper wire. Turn ignition switch ON and if fan works, there is no problem with the relay or power supply. The fan switch would be suspect.
In the fuse box there would be some relays. No relays should be working with the ignition switch OFF, unless you have any alarm system installed. To check which relay is clicking, unplg a relay at a time and while reinstalling, if the realay clicks, note its position and let me know.
If the reserve tank is not keeping sufficient coolant level, the radiator would run dry over a period of time. During running of engine, the coolant would heat up and a certain amount would move to the reserve tank and if the level is low, air would be sucked into radiator when the coolant cools down. Repetitive action would cause the radiator level to go low resulting in overheating.
Friday, March 27th, 2009 AT 9:57 AM