my Volkswagen Golf MK7 (2015-2019) heater only blows cold air what could be wrong?

Solution

1. Preparation

• Gather tools and parts required for the repair.
• Disconnect the battery to ensure safety while working on the cooling system.

2. Check Coolant Level

• Open the hood and locate the coolant reservoir.
• If low, add the appropriate type of coolant (G12 or G13 for Volkswagen).
• Check for leaks; if leaks are present, replace the damaged hoses or components.

3. Inspect and Replace the Thermostat

• Remove the engine cover if necessary to access the thermostat.
• Drain the coolant from the radiator using a drain pan.
• Disconnect the hoses connected to the thermostat housing.
• Remove the thermostat and replace it with a new one, ensuring correct orientation.
• Reconnect hoses and refill the cooling system with the appropriate coolant.

4. Test Heater Control Valve

• Locate the heater control valve, typically near the firewall.
• Disconnect electrical connector and hoses from the valve.
• Use a multimeter to check for electrical continuity (if applicable).
• Replace the heater control valve if it fails to operate properly.

5. Finalize and Refill

• Refill the cooling system with coolant to the proper level.
• Start the engine and let it reach operating temperature while checking for leaks.
• Bleed the cooling system to remove any trapped air.