Troubleshooting Left Side Trailer Light Not Working With New Bulb

Question:

Have power to Left side when tested changed bulbs but still not working

asked by: Bubba

Expert Reply:

With verified power on the power wire using a Test Light # PTW2993 but still not working with changing to a good bulb it sounds like you have either a bad ground or corrosion inside the bulb terminal. I recommend first using your test light to connect the ground wire coming from the light to a known good ground on your trailer. As your left light is the only light not working this ensures the main ground from the trailer to your vehicle is good. If the light works by using a jumper to a good ground you know you will need to find the ground connection and clean the corrosion or damage which is not giving it the proper connection.

Next you will want to check the base the bulb sits inside on the light. There could be an issue with corrosion on the connection points for the light or where the wire attaches to the light base.

If you still have issues you will want to bench test the light itself. Please let me know if you are still having issues and which light you have so I can expand on this. Images are always helpful as well.

expert reply by: Bud M