AC–59 AIR CONDITIONING SYSTEM – TROUBLESHOOTING INSPECTION PROCEDURE 1 Check voltage between terminal HR of A/C amplifier connector and body ground. ON Connect P Remove the A/C amplifier with connectors still connected C Measure voltage between terminals HR of A/C amplifier connector and body ground when ignition switch is ON and OFF. OK Ignition Switch Voltage OFF OV ON Blower ON Below 1.O V Blower OFF Battery positive voltage BE3840 NO8781 NG OK Proceed to next circuit inspection shown on matrix chart (See page AC–26). 2 Check heater relay. C Check continuity between each pair of terminals of heater relay shown below. OK Terminals 4 and 5 No continuity Terminals 1 and 3 Continuity Terminals 2 and 4 Continuity P 1. Apply battery positive voltage between terminals 1 and 3. 2. Check continuity between each pair of terminal shown below. OK Terminals 2 and 4 No continuity Terminals 4 and 5 Continuity BE1850 BE1844 OK NG Replace heater relay. 3 Check HTR fuse. OK NG Check for short in all the harness and components to the HTR fuse (See attached wiring diagram). Check and repair harness and connector between A/C amplifier and battery.