A/C - Window Fogging With A/C ON
Article No. 94-6-13Date: March 23, 1994
HEATER - NEW FUNCTION SELECTOR SWITCH ASSEMBLY AND VACUUM LOGIC
WINDSHIELD FOGGING - NEW A/C FUNCTION SELECTOR SWITCH ASSEMBLY AND VACUUM LOGIC
LIGHT TRUCK: 1992-94 F-150-350 SERIES, F-47
This TSB article is being republished in its entirety to correct the Dealer Coding Basic Part Number.
ISSUE:
In A/C equipped vehicles, the windshield may fog when the function selector knob is set in the "Norm A/C" or Max A/C" position. This may be caused by the vacuum logic in the heater and air conditioning systems.
ACTION:
Replace the A/C function selector switch assembly with a revised switch which has improved vacuum logic. Refer to the following procedure for service details.
1. Remove the function selector switch assembly. Refer to the appropriate Light Truck Service Manual, Section 12-02A for A/C heater systems or Section 12-02B for heater only systems.
2. Remove the function selector knob.
3. Remove the two nuts securing the vacuum harness and separate the harness from the selector switch.
4. Remove the screw which secures the vacuum selector switch to the A/C heater control assembly.
5. Turn the function selector switch counterclockwise and remove it.
6. For installation of the replacement switch, reverse the removal procedure.
7. Start the engine to provide vacuum, then move the function control to each of the operating positions to verify the proper airflow distribution.
8. For the heater A/C system function selector detent positions and vacuum logic, refer to the Heater-A/C System Function Switch Chart.
9. For the heater and ventilation system function selector detent positions and vacuum logic, refer to the Heater-Vent System Function Switch Chart.
PART INFORMATION
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 94-4-12
WARRANTY STATUS:
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
940613A Replace Function Selector 0.6 Hr.
Switch Assembly
DEALER CODING
BASIC PART NO. CONDITION CODE
19B888 08
OASIS CODES: 208000, 208300, 208999