1996 Bronco/F-Series

Section 12-03A: Air Conditioning System, Manual A/C-Heater

1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual

ADJUSTMENTS

Mini-Tube Vacuum Hoses

To check for proper functional control in the system, move the heater blower motor switch (18578) to HIGH. Then, move the function selector to each of its seven positions. There should be airflow from the appropriate registers, heater outlet floor duct (18C433) and nozzles and no airflow in the OFF position.

If proper airflow is not provided, look for the following:

An A/C plenum vacuum harness (18C581) which is not fully seated at the vacuum control motor (18A318).
A damaged connector between the A/C control (19980) and heater air plenum chamber (18471).
A damaged connection between the heater air plenum chamber and vacuum source.
An A/C plenum vacuum harness that is pinched or trapped.
A transposed vacuum line. This condition is evident when the color code on the vacuum line fails to match the color code on its mating vacuum nipple.
An inoperative A/C control.