This is your guide on how to install a universal relay harness wiring set with an on/off switch. This wiring kit will work with any LED light product such as the Ford F-150 LED light bar and makes them easy and safe to work with. For this guide, we will be tapping this LED light bar to achieve superior lighting in dark, off-roading situations. Keep in mind that you can still tap your LED light product into an existing harness, but you cannot control it independently and you will run the risk of it overloading.
Step 1: Before You Get Started, You Can Refer to This Wiring Map So You Have a Point of Reference. the Following Numbers Correspond to Their Respective Wiring Locations:
#3: Tap to LED light bar positive
#4: Tap to LED light bar negative
#5: Tap to battery positive
#6: Tap to battery negative
#7: Draw to vehicle interior and mount on flat surface
#8: Tap to headlight positive
#9: Tap to headlight negative
Step 2: Disable the Terminals of the Shorter Output Wires.
Skip this step if you will be using both sets of terminals.
Wrap each terminal with electric tape so the points don’t touch. Then wrap the white and black wires away from each other to ensure there is no chance of them touching. If you are using both sets of terminals, we suggest using the shorter end on whichever side the battery is situated.
Step 3: Connect the Other Set of Terminals to Your LED Light Bar for Your Ford F-150.
Tap the white terminal wire to the positive red wire and the black terminal wire to the negative black wire. Secure the tapping points with electric tape.
Step 4: Tap the Red Wire Connected to the Fuse to the Car Battery Positive and the Black Wire From the Relay to the Car Battery Negative or an Available Ground.
The fuse is connected to red wire so if your LED light bar short circuits, the fuse will blow and prevent any further damage. The relay acts as a railroad switch, directing the flow of energy to the right direction.
Step 5: Route the Button Switch to the Driver Side Interior.
The switch comes with double sided adhesive so you can place the button anywhere it’s convenient.
Start by drawing the switch portion of the wiring from the passenger side to the driver side for ideal cable management. Locate the rubber cover on the driver side and open the firewall cover. Insert the switch from the engine bay into the interior.
Step 6: Merge the Red Trigger Wire to a Headlight or Taillight Positive Wire and the Black Wire to a Ground.
The red wire is tapped into the headlight positive wire to protect the car battery from being drained as a result of neglect.
More recent models automatically turn off its headlights at night after the car is turned off. Additionally, drivers are less likely to forget to turn off their headlights than push the button to turn off their LED light bars because the latter is not a native function. For these reasons, the red wire is tapped into the headlight positive wire.