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

Is a battery included?

Light Check includes a 12 volt sealed lead acid battery, the same kind of battery that is used for the electric brake emergency break-away system.

Is the battery rechargeable?

The battery is rechargeable. A battery charger is included.

What is the life expectancy of the battery?

The life expectancy of the battery is 3 to 5 years. It is recommended to recharge the battery after each use to extend the battery life.

Does this work with trailers with LED lights?

LED lights are very bright and at the same time very energy efficient. In fact they use so little current that Light Check might show an under current fault (open circuit) because the amount of power being used is below the minimum amperage level. However, Light Check will continue to power the light circuit(s) allowing you to visually inspect the trailer lights for proper operation

What type of trailer connectors are included?

Light Check has a standard 7 pin RV style trailer wiring connector on the right side of the unit. Standard adapters are available for trailers with flat 4 pin, 5 pin flat and 6 pin round trailer wiring connectors. Such adapters are available on our "Order Products " page as well as at many of your local retail outlets.

Is a carry case available for Light Check?

Yes. A carry case is available for Light Check on the "Order Products " page of our web site. This is a great option to protect the product and easily carry it to the trailer(s).

Are packages available with adapters included?

Yes. There are a few packages available on our "Order Products " page. The packages included Light Check, a Carry Case and either 3 or 4 adapters included.

How long will the battery last before a recharge is required?

This depends on the type of lights on you trailer (incadescent or LED) and how many lights are on your trailer. We have heard from a few customers that they are able to test the lights on 20 or more trailers before a recharge is required.

Will Light Check, test my electric brakes?

We have been asked many times if this product tests electric brakes. The direct answer is No. We considered including testing electric brakes. The problem with testing electric brakes with any electronic device is that only the electrical components can be tested. However, there are many other components involved with electric brakes that can not be tested electronically. Even if the electrical components are working properly does not ensure that your total brake system is working properly.

Components that must be inspected include:
• Magnets
• Brakes shoes
• Brake drums
• Springs, levers and linkage
• Battery for emergency break-away system

Even if the electrical components (wiring and magnets) are operating properly, failure of any of the other components may render your electric brake system inoperative.

A simple electric brake system test

Raise the wheels up with a jack so you can turn the wheels by hand. You will likely do this one side at a time. Pull the switch that activates your emergency break-away brake system and try to turn the wheels. If all the wheels are locked (brakes fully engaged), the brakes are working properly. An alternative is to pull the switch that activates your emergency break-away brake system and attempt to pull the trailer with your towing vehicle.

If one or more wheel still turns freely, you know you have a problem with your electric brake system.

Testing your electric brakes this way ensures that all components (both electrical and mechanical) are working properly, including the emergency break-away switch and battery. Remember, if everything is working properly but the emergency break-away battery is too weak or dead, your emergency break-away brake system will not work.

Know your trailer

If you have a tandem or triple axle trailer, not all wheels will necessarily have electric brakes. For example, a tandem axle trailer may have electric brakes only on the front axle. So if you test the electric brakes as described here, only the front wheels would not turn.

What else to inspect

The condition of the drums, shoes, shoe return springs and hardware should also be inspected. Broken or badly corroded return springs and shoe hardware should be replaced. Adjusters should turn easily. Shoes or drums that are too thin should also be replaced. Also, try turning the wheels without the brakes applied. If the wheel does not turn freely, there could be other problems such as bad bearings, broken or misadjusted brake shoes or drums, or corroded or broken components that do not allow full release of brakes.


Trailer lights are totally electrical. Light Check provides a simple, cost effective method to test your trailer lights without a towing vehicle or another person to assist. Also, most single axle trailers do not have electric brakes. Light Check, therefore, provides a
complete solution for testing the electrical components of your trailer.

A future version of Light Check may include electric brake testing. However, it will only be able to test the electrical components of the electric brake system, not the mechanical components.

Remember, any electronic device that claims to test electric brakes is only testing the electrical components, but not the mechanical components. As mentioned earlier, even if the electrical components are working properly does not ensure that your total brake system is working properly.

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