If I remember correctly, with the heater control panel pulled out there is a plug that goes to the blower motor and the AC harness plugs there in place of the heater only harness. The harness exits the cab on the right side under the AC evaporator casing.
This the original evaporator casing on Darth, heat shield faces the exhaust manifold area to protect the harness visible in the foreground.
Bill AKA "LOBO"
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"Getting old is inevitable, growing up is optional"
Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator
Wife's 2011 Flex Limited
Daily Driver 2009 Flex Limited with factory tow package
Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413