GMC 1986 P-Truck Service Manual page 83

1B-20 AIR CONDITIONING
Port
Connection No.
Source 1
A/C Mode 2
Heater/Mode 3
OSA/REC 4
Defroster 5
Ports 6,7,8 and 9 not used (sealed on vacuum hose assembly)
45. Vacuum Source - Engine
46. Vacuum Tank (Gas)
47. Cowl
48. Plenum Valve
Select Lever Valve Operation Chart
Off Max A/C Norm A/C
Vent Vacuum
Vent Optional Optional
Vacuum Vent
Vacuum Vacuum
Vent
49. Mode Door
50. Defroster Door
51. Recirculator Door
53. Actuator
Figure 20—C-K A/C Vacuum Schematic
Bi-Level Vent
.. vac ............
....... ■
vum
Vent Optional
Vent Vent Vent
Vent Vacuum
E. Vacuum Line ■ Gary (Source)
F. Vacuum Line - Orange (Defroster)
H. Vacuum Line - Dark Blue (Heat)
I. Vacuum Line - Tan (A/C)
J. Vacuum Line - Black (Defroster)
Defrost
Heat
*
^
Vacuum
Vent
Vacuum Vacuum
Vent Vent
F-00182