Light Check trailer light test

Trailer Lights Will Eventually Fail!

Avoid legal and regulatory citations and fines. Save time and money by testing your trailer lights with Light Check.

The Quick Check for Trailer Lights

Trailer Light Check

Light Check trailer light test


  1. Connect Light Check to trailer wiring connector
  2. Turn ON the power switch
  3. Press the Select button once for Cycle
  4. Test and observe lights for proper operation
  5. Turn the power switch ot OFF when finished.

No hook-up vehicle or second person to assit.

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Product Information

Wiring Connector

The connector on side of Light Check is a standard 7 Pin RV style connector. To connect trailer lights with other type of connectors, simply use one of the adapters. Adapters are available for the 4 pin flat, 5 pin flat, 6 pin round and 7 pin commercial wiring connectors.

Select Button

Turn on the power with the On/Off power swith and press the Select button to select the desired test mode. Pressing the Select button once after turning on the power is for Cycle. In Cycle, Light Check will continue to cycle through each light circuit in 5 second intervals. The light next to CYCLE will be on as well as one of the other lights to indicate which circut is being operated.

To select one of the circuits for continuous operation, continue pressing the Select button until the light next to the desired circuit is on. The light next to Cycle will be off.

Fault and Fault Location Lights

If a problem is detected in the trailer lights, the Fault light and one or more of the corresponding Fault Location lights will turn on to indicate the type and source of the problem. The fault light will be steady-on for a low current and blinking for an over current.

Ground (GND) Connection - When is it used?

Most trailers are wired with the ground connection through the trailer light wiring harness. Occasionally a trailer will be encountered with the ground connection through the hitch, not through the wiring harness. An indication that the ground is not through wiring harness would be the Fault light is on and all three Fault Indicator lights turn on as Light Check goes through the cycle. The ground wire has a connector that plugs into the GND connector. Clip the alligator clip on the other end to a bare metal on the trailer hitch. Repeat the light tests with Light Check.

Low Battery

The Fault light blinking slowly with no Fault Location lights on indicates a low battery. Recharge the battery as soon as possible.


The internal battery will last from 1/2 to 3 hours depending on the number of lights on the trailer(s) being tested. The fault light blinking slowly with no fault indicator lights illuminated indicates low battery.

To recharge the battery, insert the round end of the battery charger wire into the Charge connector on the top of Light Check and connect the other end of the battery charger wire into a 110/120 VAC outlet.

To maintain and extend battery life, it is recommended to recharge the battery after each use.

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