Tech 1 Diagnosis - HVAC System - Electronic

VEHICLE PREPARATION
^ Connect a jumper wire from the Heater/Vent/Air Conditioning (HVAC) Control Head Connector, terminal "4" or terminal "5", to the (Data Link Connector (DLC) Connector, terminal "14". Insert the jumper through the back (wire entry side) of each connector.
^ Install the Tech 1 using the Body Systems Cartridge. When the Tech 1 asks for the model year, key in 1990 (not 1994).
^ Proceed with climate control diagnosis.

IMPORTANT: To prevent future data line communication problems, remove the jumper wire after diagnosis.