Defroster, Demister and Register Ducts

The windshield defroster hose nozzle (18490) and A/C evaporator register ducts (19B680) are attached to the instrument panel (04320) with self-tapping screws.

The demister system has a hose which attaches to each end of the windshield defroster hose nozzle and leads to two A/C side window demister and hoses (19E630) in opposite corners of the instrument panel .

Defroster Nozzle, Demisters and Register Ducts

Item	Part Number	Description
1	19E630	RH and LH A/C Side Window Demister and Hose
2	18490	Windshield Defroster Hose Nozzle
3	19B680	RH A/C Evaporator Register Duct
4	18A318	Windshield Defroster Door (Part of 18A318)
5	18471	Heater Air Plenum Chamber
6	19B680	LH A/C Evaporator Register Duct

Vacuum Control Motors

Three vacuum control motors (18A318) are used in the manual A/C-heater system:

• One is used to operate the heater and A/C air inlet duct door.
  • It is located on the A/C recirculating air duct (19C590) behind the glove compartment (06010) .
  • It opens the heater and A/C air inlet duct door to outside air with no vacuum.
• The windshield defroster door vacuum control motor is located on the LH side of the heater air plenum chamber (18471) .
  • It opens the windshield defroster door for defroster operation when there is no vacuum.
• The heater air damper door vacuum control motor is a dual-diaphragm vacuum control motor .
  • It is located on the LH end of the vacuum control motor .
  • Vacuum must exist at both diaphragm ports for full travel of the motor arm.
  • Vacuum at the top or end port of the vacuum control motor will give about half travel of the motor arm.
  • If vacuum is applied to the side port only, vacuum control motor operation is minimal.
  • If the vacuum hoses to this vacuum control motor are reversed, the vacuum control motor will not operate properly when the function selector knob (18519) is in the MIX position (refer to Airflow Schematic .