Dealer Service Information Bulletin 68-I-36 – Operating Instructions for 1968 Pontiac Custom Air Conditioning System – First Generation Firebird (1967, 1968, 1969)

Bulletin 68-I-36 — Pontiac Motor Division Dealer Service Information Bulletin, Section 1A, dated January 31, 1968. Attention: Service Manager.

Subject: Operating Instructions for 1968 Pontiac Custom Air Conditioning System.

Short answer: Owners and service personnel should understand the two rotary switches and six mode buttons of the 1968 Pontiac Custom A/C system; the Freon compressor operates automatically above freezing in any mode except VENT, and each button directs airflow differently.

There appears to be some lack of understanding as to proper operation of the new 1968 Pontiac Custom Air Conditioning system. Owners’ acceptance of this new and flexible system will be much greater if they are instructed as to its proper operation at the time of new car delivery or when cars are in for service.

The control panel should be used as follows: Set the two rotary switches on the left and right side of the control to the desired blower speed and air temperature, respectively. With the SYSTEM button in the OFF position, depress any one of the other five buttons (INSIDE, A/C, BI-LEVEL, HEATER, or DE-ICE). The system will now operate in the mode and at the temperature and blower speed selected. If ambient temperature is above freezing, the Freon compressor will also automatically operate to minimize potential fogging. If it is desired not to operate the Freon compressor, it can be shut off by merely depressing the SYSTEM button to the first detent stop, at which time VENT will appear in the left window. If any other button except SYSTEM is then depressed, the Freon compressor will again operate (temperature above freezing) until the SYSTEM button is once again depressed to VENT. An ambient switch prevents Freon compressor operation whenever the temperature is below freezing.

Air flow from the various outlets in the system is controlled by the mode buttons, in order of occurrence on the panel:

1968 Pontiac Custom Air Conditioning — Mode Button Reference
Button	Button Position	System Function
1. SYSTEM	OFF	Air door closed and blower off.
1. SYSTEM	ON	Mode as selected by other five buttons — Freon compressor operating if temperature is above freezing.
1. SYSTEM	VENT	Mode as selected by other five buttons — Freon compressor off.
2. INSIDE	Depressed	Inside air is recirculated at temperature and blower speed as desired through five A/C outlets. This mode is suited for quick cool-down in hot weather.
3. A/C	Depressed	Outside air delivered at temperature & blower speed as desired through five A/C outlets. Suited to normal hot weather operation.
3. A/C	Depressed w/VENT	Supplies air through five A/C outlets which is the same temperature as outside air temperature (control set to all blue bars) or air may be heated by rotating the temperature control toward maximum heat (all red bars).
4. BI-LEVEL	Depressed	Outside air delivered through A/C and heater outlets at temperature and blower speed desired.
5. HEATER	Depressed	Outside air delivered through heater outlet at temperature and blower speed desired. Suited to cold weather operation.
5. HEATER	Depressed w/VENT	Outside air delivered through heater outlet at temperature and blower speed desired. Freon compressor is off.
6. DE-ICE	Depressed	Outside air delivered to windshield at temperature and blower speed desired. System button “ON” is recommended at all times for removing fog or ice from the windshield.