The heater control valve is spliced into the heater core hoses. It can be tested by attaching a hand vacuum pump to the valve to draw and release vacuum. If during this procedure the heating system functions properly, the valve is not defective. Check for vacuum leaks in the control panel or restrictions in the coolant system.
REMOVAL & INSTALLATION
Allow the vehicle to cool before performing this procedure.
- Label and disconnect all heater hoses attached to the valve.
- Disconnect the vacuum hose which controls the valve.
- Remove the valve.
- Installation is the reverse of removal.