My wife has a 1996 Honda Accord Dx. Last Sunday we were out when she realized her temperature gauge, in the car, wasn't working. Then we went straight to Advanced Auto, where they told us it was the coolant temperature gauge. So the next day my wife and me changed the coolant temperature gauge. When we turned on the car it start over heating (the gauge in the car was red line) within minutes. So the temperature gauge in the car now works. Then we changed the thermostat, radiator cap, and the coolant temperature sensor for the ecm. After that the car still is over heating. After that we replaced both ect switches but now the fans won't come on. If you turn on the a/c both fans turn on but when you turn the a/c off the fans cut right off. How do I get the fans to come on? I know they work because they turn on when the a/c comes on.

 

The temp guage says it's overheating OR
You know the engine is really overheating? Head temp over 200 degrees.

How did Advance auto DIAGNOSE the temp gauge was the problem?

The cooling fans don't give a flying flip if the gauge says hot, they are controlled by the temp switch at the T-stat housing.

you need to verify the gauge is working correctly and what the real engine temp is.

Did any one check the temp sending unit connection at the head? If that wire is grounded it will make the temp gauge read all the way hot; likewise if it is not connected to anything the gauge will never move. [sorta like the original problem.]

 

I agree. A side note if you did not catch it from his reply, there is a temp switch and temp sensor. the sensor is for the ecm which goes to the guage (no connection to the fans). the temp switch is what tells the fans to turn on or off. if you replaced the sensor but not the switch, change the switch too. it is also possible you broke the temp switch when replacing the sensor since they are so close to eachother and fragile.