Troubleshooting Hints

1. Check for vacuum at the BLACK hose from the vacuum Source to the Check Valve, to the Vacuum Tank, at BLACK hose from engine, and at VIOLET hose the Heater-A/C and Rear Defogger Control Assembly.

2. Check operation of Temperature Valve by moving Temperature Lever rapidly back and forth several times. Listen for valve to strike the stop at each end of its track. If the sound indicates that the valve is not fully closing or opening, check mechanical linkage between valve and Temperature Lever.