I am trting to help my son figure out the overheating problem with his 93 civic 2door 5 speed vtec engine. It looks loke the relay is good, and fan will work with 12 volts sent to it. Its overheating and the fan wont kick in. Coolant level is good and circulating. Any ideas?

 

check your thermostate switch. if there is power to one side, the thermostate switch is not allowing power to go to the motor to power the fan. thermostate switch is bad.

 

I have replaced the thermostat switch and stll no luck. Fan will turn on with direct 12v power from the battery. Wondering if thermostat is working and does it have any bearing on the operation of the thermostat switch?

 

when the water temp gets to a certain degree, the thermostat switch which has 12v on one side will open and allow the power to continue to the fan. check to see if you are getting voltage to one side of the thermostat switch. switch works on temp.

 

Where does the thermostat switch run from and to on the circut? I think maybr a relay could br bad on the run or perhaps a short in the wire. I will check both wires comming off the the thermostat switch when the car warms up and see if it gets 12v. I dont think it is as the fan is not comming on.