Right Tail Light Not Working on Trailer With New Light and 7-Way Connector

Question:

New lights and connector on 7 pole trailer, cleaned all mounting bolts prior to installing. Only getting 2 Amber and left tail lights to light. Blinkers working fine. Cant get right tail light to work when plugged in to tow truck. Does light when jumper wire from another battery is touched to its brown/green wire end.

asked by: Ed N

Expert Reply:

If the right tail light on your trailer is working properly when you connect it to an alternate source of power at the 7-Way, and you have verified that the ground is secure and has a clean, metal-to-metal contact, then the problem is most likely on your truck.

Check to see if there is any rust, corrosion, or debris in the connection itself. Clean the connector if there was any and use some Dielectric Grease # 11755 for a strong connection and to help prevent corrosion and moisture affecting it.

If you are not getting a signal on your right tail light then you will want to test the pin in the 11 o'clock position with a Circuit Tester # PTW2992. If you are not getting a signal, or if it is a weak signal, then you will want to check that wiring along your truck looking for any place that it is corroded, bent, damaged, or exposed. You can replace any sections (or the whole wire) with 16 Gauge Wire # DW02359-1 and Butt Connectors # DW05744-5.

If you are getting a good signal, or if you replace the wiring and you are still experiencing this issue then you will want to take your truck and trailer to your local trailer shop and have a qualified mechanic inspect it since they will be able to physically see what is going on.

I have attached one of our helpful articles that is about trailer wiring for you to check out as well.