Q: I have a 2009 chevy Aveo, and my temperature gauge is below the cold line. It my heat is blowing out semi warm.

The lack of heat being generated by your system may indicate a clogged heater core. The [heater core]((https://www.yourmechanic.com/services/heater-is-not-working-inspection) is a small radiator like unit that circulates the hot coolant from the engine through the heater core which then uses this warm coolant to heat the inside of the car with the help of the blower motor that blows the warm air through the vents inside the car. The other possibility is that the thermostat may not be allowing the engine to reach a normal operating temperature and since the engine’s warm coolant is the essential source of the heater core supplying heat to the inside of the vehicle, this can impact the warmth of the heat inside the vehicle.

The "HOLD" light may suggest that the engine and/or transmission are not warming up to normal operating temperature which may also explain the lack of heat being produced. If the engine and transmission are not warming up due to the thermostat staying open then this can occur. You are going to need to use a scan tool to see what temperature the computer is seeing. If it is different from the gauge then you may have a short in the instrument cluster. The best place to start is scanning the computer with the right scan tool. I would suggest having an expert from YourMechanic come to your location to take a look at your vehicle to determine what may be causing this.