water indicator and light engine failure

I'll do! And i'll send you data. Thanks. Gianfranco OBD code is 15 . and Ecu read -25f !!!!!! here in Italy we have an outside temperature of 0 degrees Celsius, but motor water is hot, the heat works even if the thermostat is closed and we have no air bubbles in the water circuit !!!!

I don't think you have any coolant issues at all. First, make sure your grounding straps were installed, installed correctly, then it is time to test the ECU. The intake air temperature should not be ANYWHERE near 293F when it is 0C outside unless you are really demanding performance from the engine.... it doesn't make sense. Use a digital volt-ohm meter and check how much resistance you have between the engine block and the frame of the truck. Also, make sure you have a good connection on the grounding strap for the battery. If these are good, and you are SURE there are no grounding issues, then it is time to test the temperature gauge, and the ECM for proper function.... To help testing grounds, use a pair of jumper cables. Connect both clamps on one end to the negative battery terminal, and connect the other end to the engine and frame.