Running Lights Not Working On Trailer Connected To 1999 Toyota Land Cruiser

Updated 10/29/2014 | Published 10/28/2014

Products Featured in This Question

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

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Dielectric Grease for Electrical Connectors, 2 oz.

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LCD Digital Circuit Tester

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Question:

Hello. I have a 1999 Toyota Landcruiser with a 7 pin trailer connector. My trailer has electric brakes fitted on it. The brakes and lights on the trailer are all working except for the parking lights. After some troubleshooting, I believe that the converter box on the Landcruiser is faulty and not passing the proper voltage for the parking lights. I see on your web page that you have the converter boxes with the four pin trailer plugs but I was not able to find a converter box that is set up for the seven wire plug. Will the converter box with the four pin plug work if I cut the four pin plug off and wire it to my seven pin plug? Do you have an alternate solution? Thank you.

asked by: Jeff

Expert Reply:

The first thing I recommend is to make sure you isolate the problem causing the running lights not to work on your trailer.

You can check the lights on the trailer with a 12-volt power source while disconnected from your 1999 Toyota Land Cruiser. Many times, there can be a broken wire, a loose ground, or corrosion build-up that is causing the problem. If everything checks okay, you can then move to the vehicle.

Check the connector on the rear of your 1999 Toyota Land Cruiser to see if it has been damaged or become corroded and not sending the signal. I recommend using a circuit tester like part # PTW2992 to test the connector functions for current.

Then use the circuit tester and check the wires leading from the converter to the trailer connector on the vehicle. If you have current on all the wires you can check the connector to see if by chance it has been damaged or become corroded.

If you check the wires coming from the converter box and see it has no current for the running light circuit, you will want to check the wires going into the converter to make sure there is not a problem with the wiring on the vehicle.

If you find the problem is on the converter box, then I recommend part # C55365. This will replace the converter box and easily installs by plugging directly into the Land Cruiser wiring. You can do just as you mentioned by cutting the 4-way plug off the harness and wiring just the light circuits from the 7-way connector to the 4 wires leading from the converter.

When working with electrical connectors I recommend using dielectric grease like part # 11755. This keeps dirt and moisture out of the electrical connections and helps prevent corrosion.

I have attached a link to a couple of helpful articles you can check out.