Trailer Lights Not Working on Metal Craft Crestliner Boat Trailer

Updated 05/09/2011 | Published 05/07/2011

Products Featured in This Question

Optronics Combination Trailer Tail Light - Submersible - 7 Function - Incandescent - Passenger Side

(1237)

$14.94

Hook Probe Circuit Tester

(60)

$12.41

Question:

Had my boat for 8 yrs now, went to haul it to the carwash for a little spring clean-up, and I have no running lights,no flasherson trailer with truck lights on, when truck lights off,flasher light shows up on bottom 3 center running lights of trailer rear. No brake lights on tail lights , but shows up also on bottom 3 running lights. Left and right turn signals work, without truck lights being on.never had any problems for the last 8 years, nothing has changed with the wiring or my truck. Dodge Ram 2500 Its gettin juice,but I can`t figure out why it would be any different now. I did have an ECU go out on the Dodge a few years ago which caused a no left turn signal on my camper and boat. Is there some way I can test the plug to see if it`s the trailer or my truck? Would a bad ground on the trailer cause all this ?

asked by: Louis M

Expert Reply:

You can test the connectors on the Dodge Ram 2500 and the boat trailer with a circuit tester like part # PTW2993. I am including a link to a FAQ page on trailer wiring that will show you the functions of each pin on your connector, depending on if it is either a 4-Way, 5-Way, 6-Way, or 7-Way. This will help you determine if there is a problem with the wiring on the vehicle or the trailer.

Also, I would recommend to test the ground connections on the vehicle and the trailer. When you find that some of the lighting functions work, but not all of them it is always best to check the ground connections.

I would check the ground on the connector on your Dodge Ram to make sure it is attached to a good, clean ground on the vehicle frame.

Also, check the ground on the trailer connector which should be attached to a good, clean ground on the frame of the trailer.

The last thing to check is the tail light assemblies on the boat trailer to make sure they are grounded. Trailer tail lights can be grounded in one of two ways. The first way is the tail light assemblies can be grounded by a separate wire coming out of the back of the tail light and attached to the trailers frame. The second way is the tail lamp assembly is grounded through the mounting bolt that attaches the tail light to the frame.

expert reply by: Jeff D