Troubleshooting Modulite Installed on on 2008 Toyota Rav4

Question:

I have part # 118412 installed. The running lights brown wire is hot even with the ignition off. Brake lights and turn signals work fine. I checked the ground wire and its fine. Do the modulites go bad? What else can I look for that might be causing the prob? Thank you!

asked by: Jeff

Expert Reply:

Modulites can occasionally short out. I would recommend using a circuit tester like part # PTW2993 to test the wires going into the converter box. Test only the wires that go to the taillight assemblies, not the red wire that runs to the battery. If you show no power going into the converter box from the taillights, then something in the converter box has shorted out and the harness will need to be replaced.

If you determine that the converter has shorted out and needs to be replaced, I recommend taking the time to examine your trailer wiring to ensure that it is in good shape. Start with the connector itself, making sure it is not corroded or damaged. Trace each lighting circuit back to its lamp, looking for pinched wires or wires with nicks or worn insulation that would cause the circuit to ground out. You will want to repair any issues you find before replacing the modulite or you will short out the new one.

expert reply by: Mike L