In the year 2023, many people still face the issue of their trailer brake lights not working when the running lights are on. This can be a frustrating problem, especially when driving at night or in low visibility conditions. However, there are a few common reasons why this issue occurs, and some simple troubleshooting steps you can take to resolve it.
1. Check the Bulbs
The first step is to check the bulbs in the trailer brake lights. Over time, bulbs can burn out or become loose, causing them to stop functioning properly. Remove the bulb housing and inspect the bulbs for any signs of damage or corrosion. If necessary, replace the bulbs with new ones specifically designed for trailer brake lights.
2. Inspect the Wiring
Another common cause of trailer brake lights not working when the running lights are on is faulty wiring. Inspect the wiring harness for any loose connections, frayed wires, or signs of damage. Ensure that all the connections are secure and free from corrosion. If you find any issues, repair or replace the wiring as needed.
3. Check the Fuse
One of the simplest and most overlooked causes of trailer brake lights not working is a blown fuse. Locate the fuse box for the trailer lights and check the fuse for the brake lights. If the fuse is blown, replace it with a new one of the same amperage rating. It’s always a good idea to carry spare fuses with you in case of emergencies.
4. Test the Brake Light Switch
The brake light switch is responsible for signaling the trailer brake lights to turn on when the brakes are applied. Use a multimeter or a test light to check if the brake light switch is functioning properly. If it’s faulty, replace the switch to restore the brake lights’ functionality.
5. Consider a Bad Ground Connection
A bad ground connection can also cause trailer brake lights to stop working when the running lights are on. Inspect the ground wire for any signs of damage or corrosion. Ensure that the ground wire is securely connected to the trailer frame or another suitable grounding point. Clean or replace the ground wire as necessary.
6. Look for Trailer-Specific Issues
Sometimes, trailer-specific issues can cause the brake lights to malfunction. Check if the trailer has a separate wiring harness for the brake lights and running lights. Ensure that the harness is properly connected to the vehicle’s wiring system. Additionally, some trailers have a separate relay or module for the brake lights. Inspect these components for any signs of damage or malfunction.
7. Consult a Professional
If you have exhausted all troubleshooting steps and the trailer brake lights still don’t work when the running lights are on, it may be time to consult a professional. A professional mechanic or trailer specialist will have the necessary tools and expertise to diagnose and repair the issue effectively.
Having trailer brake lights not working when the running lights are on can be a frustrating problem, but it’s not an uncommon one. By following the troubleshooting steps mentioned above, you can identify and resolve the issue yourself in most cases. However, if the problem persists, don’t hesitate to seek professional help to ensure your safety on the road.