(a) Blend Door Actuator: The blend door actuator is responsible for controlling the flow of air from the heater core (for hot air) or the evaporator (for cold air) to the cabin. If the blend door actuator fails, it may cause the temperature control module to malfunction, leading to the 'thumping' noise and the inability of the system to switch over to hot air.
(b) Temperature Control Sensor: The temperature control sensor monitors the temperature inside the vehicle to ensure proper regulation of the heating and cooling system. If the sensor fails or is malfunctioning, it may provide incorrect readings to the temperature control module, causing the system to malfunction and resulting in the 'thumping' noise.
(c) Wiring Harness Issue: There may be a fault in the wiring harness connecting the temperature control module to the blend door actuator or the temperature control sensor. Broken wires or loose connections can disrupt communication between the components, causing the system to malfunction and produce the 'thumping' noise.
(d) Faulty Temperature Control Module: In some cases, the temperature control module itself may be faulty, leading to the problems described.
(e) Heater Core Issue: If the heater core is clogged or damaged, it may cause the system to function incorrectly, resulting in the 'thumping' noise and the inability to switch over to hot air.
Recommendation:
Given the complexity of these components and the need for accurate diagnosis, it is recommended that you take your vehicle to a qualified mechanic or automotive repair shop to have the issue inspected. The mechanic will be able to perform the necessary tests and pinpoint the exact cause of the problem, ensuring proper repair and resolution of the 'thumping' noise and hot air issue in your Ford Explorer.
