The cooling fan on my 96 civic is not kicking on and thus my car is overheating if I stand still for too long. I have a copy of the cooling fan circuit and I am in the process of diagnosing the complete circuit. What I am unclear about is:

1) The the cooling thermostat switch actually turn the fan on and off or does the ECU, or both? The circuit clear shows the circuit wired to be controlled by the cool thermostat switch on the motor, but its also connect to the ECU. My guess is it purely so the ECU knows if the fan is on or not, but cannot turn it on or off. Can anyone confirm?

 

fan circuit is powered with key in run position I'm not looking at the schematic @ this time. All the fan switch (on thermostat housing) does is close the circuit path to ground and completes the circuit.

Easy test, unplug fan switch and jump the 2 pins on the harness with a paperclip, fan comes on, check continuity through switch while engine is hot.

Most often, fan switch goes bad. Very basic circuit to troubleshoot.


Modified by Echo7847 at 12:16 AM 7/27/2006