Rep Power: 0

Hey guys I'm sure this will be a pretty dumb question for most but I was wondering about the gauge in the dash and where it gets it's signal. See here's the issue, I have a check engine light illuminated and the trouble code it gives is PO0118, which is supposed to be a coolant switch over temp. I think. Anyway the gauge reads perfectly in the middle of it's range and you can see that it's working as the car warms up from being cold, it never runs hot according to the gauge and the engine temp. when I open the hood seems fine. Now there is a switch just below where the upper radiator hose enters the engine, is this the cause for my engine light? Where is the switch located that operates the gauge?
Thanks in advance for any input!

 
Rep Power: 188

I think there are 2 sensors. 1 for the gauge, 1 for the computer. i don't know why they aren't tied together or why not just 1 sensor since they aren't exactly redundant.

 
Rep Power: 518

It's a sensor, not a switch. The coolant temp sensor for the computer is on the end of the head below the distributor. 2 wire sensor. The sensor for the gauge is in the same area, only it uses a single wire. Don't replace the wrong one.

 
Rep Power: 0

Thanks for the thoughts guys! I don't suppose driving it with the light on would cause any trouble would it? Seems like the car is hard to start when its hot now. Every once in a while I have to turn the thing over a bunch, almost like its out of gas, but then runs fine. Hope I didn't hurt anything...

 
Rep Power: 518

It's hard to start because the computer has no clue what the real engine temperature is. This COULD lead to cat damage if it tries to dump in far too much fuel.

 
Rep Power: 0

Ok I replaced the sensor, fingers crossed no damage other than my pride. Thanks for the help!

 
Rep Power: 0

Just wondering what year your civic is. Mine is 97 and it can't start when its too cold. Suspect the same issue. Did replacing the sensor solve the problem?