Mac ... 10/8/2012
2001 Volkswagen Beetle GLS 4 Cyl 1.8L
Does this vehicle have an hot water control valve, the heater does not work.
Measure the two heater core hoses at normal operating temperature. With full heat commanded and blower motor on High, I would expect to see roughly a 20-30 degree difference between the hoses. An extremely large difference (60 degrees or so) would indicate a completely plugged heater core that is not allowing flow. A small difference (5 degrees or so) would indicate a partially restricted heater core that is only allowing coolant to flow through a small portion.