yo; here are the instructions by Draw Tite:
http://65.196.229.70/pdf/N5500.pdf
esp. "...For tow vehicles other than 1989-91 Ford E and F series trucks and vans:
• Determine which side of the stoplight switch is the cold side. To determine
the cold side probe the terminals of the switch with a test light until one if
found that is only on when the brake pedal is depressed.
• Using the wire tap provided, splice the brake control’s red “ STOPLIGHT” wire
to the attached to the cold side of the stoplight switch as determined above..."
what else do you need?
