HAC was definitely optional, and the California trucks didn't have them because of smog restrictions.

If you need a diagram that doesn't show it, look for one for a 1981 California truck. If you do have an HAC, it will be a brown colored hockey puck looking thing over by the fuse box behind the battery.


My Truck: 1987 XtraCab DLX 22R 4WD 5 Speed Manual
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"Speed has never killed anyone. Suddenly becoming stationary, that's what gets you." -Jeremy Clarkson