HVAC Control Head - Inoperative, No Display

BULLETIN NUMBER:
93-1B-24

SECTION:
1B

NUMBER:
6

CORPORATE
REFERENCE NUMBER:
261210

DATE:
November 1992



SUBJECT:
HVAC CONTROL HEAD INOPERATIVE - NO DISPLAY (RECYCLE IGNITION SWITCH/RECONNECT BATTERY)

MODELS:
1990-93 C/K AND TOPKICK/KODIAK TRUCKS



The HVAC control head on some 1990-93 model year C/K and Topkick/Kodiak models may not illuminate when the vehicle is first started. This condition is much more likely to occur after a battery disconnect or control head replacement but may occur after any ignition cycle.

The condition is not permanent, it stems from the control head not receiving a correct signal when the ignition is turned on.



Recycling the ignition switch may bring the control head back to normal operation. If cycling the ignition does not work, disconnect and reconnect the battery making sure that a good electrical connection is maintained when reconnecting (avoid "chattering" the battery line).