In the engine bay near firewall on the passenger's side hanging down low between the the heater and vacuum hoses - the heater tap will have failed.
This:
Around $25 from Malz, Repco etc and you will need to put it on ramps to get under and replace it and be prepared to get splashed with coolant unless you drain it first.
The butterfly valve inside sticks and detaches from the vacuum operated spindle arm.
Linear Mode
