Since I bought my 98 civic ex in '07 the temp gauge hasn't worked. It really hasn't bothered me until now. There have never been any overheats or anything of that nature either. Also, I noticed the radiator fan wasn't coming on. I've just replaced my thermostat with no change.

I'm assuming the problem with the fan is the ECT switch as I've unplugged and jumped it together and the fan came on. As for the temp sensor, I've got no idea. I'm pretty sure it's the single yellow and green wire that is next to the distributor. I tried to jump that to a part of the engine to see if the needle moves at all and it appears that it does not.

What else can I try?