As long as the bulb is a standard
incandescent bulb, you can wire it to operate with relays. You must use 5 pin relays. You will need 4 of them
(running, brake, left and right).
Cut the "hot" wire going to the bulb/socket. Crimp on a female spade/"faston" connector on both ends. Make sure to use fully insulated connectors or heat shrink tubing.
- The wire going to the bulb connects to pin 30
- The wire coming from the rest of the towed vehicle goes to 87A
- The wire from the towing vehicle goes to pin 87 AND pin 86
- Pin 85 goes to ground
EDIT : If any of the bulbs are "true" LEDs
(not the aftermarket add in ones), like possibly the high mount brake lamps, it is a trickier. You need a current limiting resistor and the size of the resistor depends on the requirements of the LED(s)
