Parts for your 2020 Mitsubishi Asx-Heater tap

2020 Mitsubishi ASX heater tap – is it fitted, and does it matter?

Based on technical references, the 2020 Mitsubishi ASX (also sold as Outlander Sport/RVR) does not use a heater tap (heater control valve). The Mitsubishi Motors Service Manual for MY2019–2020 ASX/Outlander Sport shows continuous coolant flow through the heater core, with cabin temperature managed by an air-mix (blend) door driven by an electric actuator in the HVAC unit. The cooling system diagrams in the manual do not show a heater control valve. Likewise, the Mitsubishi Electronic Parts Catalogue (ASA/EPC) for 2020 ASX contains no listing for a heater tap/water cock, and common aftermarket catalogues for this model don’t list a heater control valve either. Put simply, there’s no heater tap on a 2020 ASX.

Why doesn’t the 2020 ASX use a heater tap? Mitsubishi engineered this platform to regulate cabin heat with an internal blend door rather than cutting off coolant to the heater core. That design brings a few wins for owners and techs:

• Fewer leak points and hoses to fail, reducing cooling-system dramas.
• Quicker warm-up and demist as the heater core stays hot, improving comfort and safety.
• Stable engine thermal management and simpler plumbing, which helps reliability and keeps costs down.

What should be serviced instead? While there’s no heater tap to replace, the ASX still benefits from routine cooling and HVAC attention:

• Coolant: Replace at the interval in the service schedule using the specified Mitsubishi long‑life coolant. Old coolant can corrode the heater core and reduce heat output.
• Cabin filter: A blocked filter starves airflow through the heater core and makes the system feel weak.
• Air‑mix (blend) actuator: If temperature won’t change or sticks hot/cold, the actuator or blend door may need calibration, repair or replacement.
• Heater core: If heat is poor despite correct thermostat and coolant level, a back‑flush of the core can restore performance.
• Hoses and clamps: Even without a heater tap, inspect heater hoses for seepage, swelling, or age‑related cracking.

If someone’s chasing a “heater tap” fault on a 2020 ASX, they’ll be looking in the wrong spot. Diagnostics should focus on coolant condition and level, thermostat operation, HVAC blend door control, and airflow through the core.

Popular questions

Does the 2020 Mitsubishi ASX have a heater tap?
No. The 2020 ASX uses a constantly hot heater core and controls cabin temperature with an electric air‑mix (blend) door inside the HVAC box. There’s no heater control valve in the engine bay.

How does the ASX control cabin temperature without a heater tap?
An actuator moves the blend door to mix warm air from the heater core with cooler air, delivering the temperature set on the dial. Because the core stays hot, warm-up and demist are nice and quick.

What should be checked if there’s no heat or it’s stuck hot?
Start with coolant level/quality and the thermostat. Then check the cabin filter and listen for the blend door actuator cycling when changing the temperature. If airflow is fine but heat is weak, a heater core flush may help.