Can a Taillight Converter Module Go Bad After Working Properly for Months

Updated 05/08/2020 | Published 12/09/2012

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T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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$74.62

Dielectric Grease for Electrical Connectors, 2 oz.

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Digital Multimeter with 42" Long Test Leads - LED Display

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Question:

Is it possible for the Circuit Protected Modulite Powered Taillight Converter to go bad? I installed this several months ago and now it does not work. Using a test light, all circuits work beforeinch the converter, but nothing works afterinch the converter

asked by: Tommy S

Expert Reply:

It is possible for a taillight converter module to go bad. If your circuit testing shows correct signal inputs to each input pin of the module, but no output from the module, then the module could be blown.

Please refer to the trailer wiring troubleshooting guide attached. This page offers information about the likely causes for a failed module and how to isolate the problem.

Any one of a number of issues can cause failure of a module. If the module suddenly stopped working and there are no visible problems with connectors, it is possible that internal trailer wiring is the source of the problem. Trailer wiring can during normal use rub against internal metal surfaces and eventually lead to a short. A failure of this type provides no warning and a dead short can damage a wiring harness.

A bad ground connection is another common cause for module failure. It is important to check ground connections throughout the circuit, from the converter all the way through to the trailer taillight bulbs. A loose ground connection, or wet or corroded bulbs or bulb sockets could cause failure. Verify that the white ground wire to the module is tightly secured to a bare metal surface or better still to an actual grounding point.

Another potential cause is that your trailer is drawing more amperage than the harness can handle. Depending on the number of lights on your trailer, it is possible that the total current draw exceeds the limit of the TowReady harness, which can handle 4.2 amps for tail lights and 2.1 amps per each stop/turn light. If your trailer has a large number of running lights, for example, you may be pulling too much current. You can test this with a multimeter such as # PT89ZR.

You will want to find and correct the cause for the module failure before installing a new one; otherwise the new module could also fail. I always recommend an application of dielectric grease on all connections to help protect them from moisture.

expert reply by: Adam R