Оригинальный сообщение: DrGlowire ,
Yes, that is weird that the temperature gauge shows hot when the heater fan is on and you are going uphill or over 50mph. The heater is linked to the engine cooling system and it should transfer heat from the engine to the passenger compartment and reduce engine heat. My guess is that it may be a faulty sensor, loose or dirty connection on the sensor or the gauge. You did not mention if your garage checked the sensors or the cooling system, try going back and have them check the cooling system and sensors/connections.