Side marker lights are required on any vehicle driven or being towed on highways. Check with your state rules, but most states require red marker lights on both tail lights, and amber marker lights mounted near the front of the vehicle. Marker lights must be visible from each side of the vehicle.
Wiring marker lights to either your vehicle or trailer is not complicated and can be performed with a minimum of tools and expertise.
Things You'll Need
- Wire cutters
- Wire strippers
- Wire splice connectors or butt connectors
Identify the appropriate power wire for marker lights. On a vehicle, this will be the wire supplying the parking lights or rear tail lights. For trailers using the standard four-wire scheme, the orange or brown wire will be the correct source for marker lights.
Examine the marker light, and determine the "hot" wire. This will be any color but black, but most commonly white.
If there is only one wire, this is the "hot" wire.
Using a splice connector, attach the hot wire to the power wire identified in Step 1. A splice connector allows you to splice a wire to another wire without the need to make any cuts. See the Resources for a sample splice connector.
Connect the black wire to ground. If your vehicle has a ground wire easily available, you can connect to that. Most trailers do not have a ground wire, but rely on the chassis of the vehicle to serve as ground.
The ground wire can be connected to the chassis by a screw, clip or any other means to assure electrical contact. Use sandpaper to expose bare metal to assure good connectivity.
Verify the marker lights are illuminated at the same time as the vehicle tail lights.
Tips & Warnings
- Some marker lights may have only one wire, and rely on the mounting screws to make the ground connection.
- If your trailer is exposed to salt water, consider sealing the ground screw contact with epoxy to avoid corrosion.
- Sample State Vehicle Regulations
- "Chapman Piloting & Seamanship 65th Edition;" Elbert S. Maloney; 2006
How to Wire Utility Trailer for Lights
Utility trailers need lights---brake lights, running lights and signal lights---for safety reasons. It is also against the law in many states to...
How to Install a 4 Wire Trailer Light Connector
Four wire trailer light connectors the typical type of connection used for pulling small to medium boat trailers and small utility trailers....
How to Wire a Trailer Tail Light
Trailer tail lights and side marker lamps are connected electrically to the automobile tail lamp system. These lights are used for providing...
How to Wire LED Trailer Lights
Over the past few years LED, or light emitting diode, lights have become evermore popular. The reason is economic, and its a...
How to Troubleshoot Utility Trailer Light Wiring
Utility trailers offer a versatile means to haul an assortment of loads. Their open design allows loads of various sizes and shapes....
How to Troubleshoot the Blinking Light on a GE Ice Maker
A GE ice maker has a green light indicating that the ice maker is turned on and operating. If there is a...
What Are Side Marker Lights?
Side marker lights are illumination devices attached to the front and rear sides of motorized vehicles and trailers. They function as auxiliary...
Homemade Trailer Light Tester
Testing trailer lights after replacement of a lamp or a complete re-wiring job generally requires connecting the trailer to the tow vehicle....