Using Center Light W/O Relay
Written by Wagon78 from the USMB.
You can make a working centerlight with a DPDT switch if you don't have the "official" relay, switch and harness. I got a 10A DPDT switch at Radio Shack that works fine.
The wires below are what come from the center light braket assembly. Connect to the switch as listed below:
Black - Lamp (-). Connect to chassis/Batt (-).
Red - Lamp (+). Connect to Pole#2A on DPDT Switch.
Black/Red Stripe - Door Motor Power. Connect to +12V
Green/Red Stripe - Connect to Pole#1 common on DPDT Switch.
Green/White Stripe - Connect to Pole#1A on DPDT switch.
Green - Connect to Pole#1B on DPDT switch.
You also have to connect +12V to the Pole#2 common on the DPDT switch.
There are some slip rings inside the motor unit that provide power to the door raise/lower motor. Gaps on the slip rings are what stop the motor when the door is open or closed. If the door opens when it should close or vice-versa, swap the green/wh and green wires.
DPDT means double pole double throw. Radio Shack is an electronics store that is in many parts of the USA in malls.