Heated Inlet Air System (HIAS)

4-156 ENGINE
1. Ensure all vacuum hoses and the cowl to air cleaner flexible connector are installed properly and in good condition.
2. With engine cold and engine compartment temperature less than 84° F, snorkel heat control door should be in the up (heat on) position.
3. Start engine and run until normal operating temperature is reached. Check air temperature entering snorkel or at the sensor. When air temperature entering outer end of snorkel is above 112° F, the heat control door should be in the down (heat off) position.
4. Remove air cleaner from engine and allow it to cool down to 84° F.
5. Connect a hand operated vacuum pump to sensor and apply 15 inches Hg vacuum to sensor. The heat control door should be in the up (heat on) position. If not, check vacuum motor.
6. To check vacuum motor, apply 10 inches Hg vacuum to motor. The heat control door should be in the full up position. If not, replace air cleaner body assembly.