Start with checking the fuses when your coolant temperature gauge isn't working. When the temperature indicator keeps getting hotter and hotter during driving, check the issue guide. When turning on the cold engine, if the temperature gauge shows the hot reading right away, you'll need to remove the wire connected to the temperature sensor unit in the intake manifold near the throttle body base. When the temperature gauge reading goes down when you check the sending unit, replace that part. If the reading stays high, look for connections to ground or check the gauge for possible malfunction. When the engine gets warm and troublefiring isn't found in the fuses, park the car, disconnect the sending unit wire, and attach it straight to a clean engine ground. Press the ignition button without starting the engine: if the needle moves to Hot, then get a new sending unit. If the gauge doesn't show anything, one of two things could be wrong: there's an electrical connection problem or the gauge is damaged itself. Open the
Radiator cap when the engine is cold to let pressure out, then put the cap back to lessen coolant loss during the sending unit change. Detach the wire from the sending unit, put a thin layer of sealant on the threads, undo the sending unit from the engine, put the new one on fast to avoid coolant spillage. Make sure the new sending unit locks tightly into place, hook up the wire, refill your cooling system, test the engine to see if anything leaks or works properly.