A customer complains that the heater works sometimes, but sometimes only cold air comes out while driving. Technician A says that the water pump is defective. Technician B says that the cooling system could be low on coolant. Who is right

As the complaint was that the car heater works at times but at other times it blows cold air, then the main culprit would be the thermostat. However, Technician B may partly be right as the coolant level om the cooling system could determine the working level of the heater also.

Explanation:

Actually, the thermostat determine the temperature level of the engine with which the car system works with to produce necessary heat whenever the heater is turned on.

Technician B is right.

Explanation:

In order to make sure that the the temperature in the car is kept at constant proportion automobiles are made to have a coolant system or a cooling system. Now, in the above question, the customer said during driving that the heater works sometimes and sometimes only cold air comes. The second technician that is technician B is right because the reason behind the customer's complaint maybe because of low coolant.

The car coolant system might be low because there is blockage in the thermostat or a leak in the radiator.