I have a 02 WRX and I have the optional gauge package. Where does the temp gauge in my cluster next to my fuel gauge and the one in my optional package measuer from. they have to be different because when i drive hard the optional one goes up a little but the regular one dosent. any i idea?

 

I believe the one in the guage cluster next to the fuel guage measures from the radiator. I think there is a sensor that taps into it and that is whats used. Im not positive about this, but in most cars I think thats how its done. Usually aftermarket guages (essentialy what the optional package is), are tapped into one of the coolant lines. Again, im not positive, but at least this is a starting point. But the optional guage measures egt's I thought, which would mean its tapped into your exhaust manifold.