Thermostatic Air Cleaner: Testing and Inspection
AIR CLEANER TEMPERATURE SENSOR1. With ambient temperature less than 75° F and engine cold, remove components necessary to observe position of duct door.
2. Start engine and ensure that duct door is in full heat position.
3. Allow engine to warm up, ensuring that door begins to open for fresh air at specified temperature for particular sensor. Brown sensor should begin to bleed off vacuum at approximately 75° F, black, clear or pink sensor at approximately 90° F, and blue, green, or yellow sensor at approximately 105° F.
4. Install components removed in step 1.
Fig. 3 Cold weather modulator operating chart:
COLD WEATHER MODULATOR
1. Apply 16 inches Hg vacuum to motor side of modulator.
2. Ensure that vacuum holds or leaks according to ambient temperature and temperature sensor color, Fig. 3.
VACUUM MOTOR
Apply vacuum to vacuum motor and ensure that door stem pulls up and stays up until vacuum source is eliminated.