Running Lamp Circuit on Thule TH665C Transporter Combi Cargo Carrier Not Working

Updated 02/12/2021 | Published 02/11/2021

Products Featured in This Question

Replacement License Plate Bracket with Light for Thule Terrapin Hitch Mounted Cargo Carrier

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$37.39

Grommet for ST33 Series Tall Rectangle Flush Mount Trailer Lights

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Hook Probe Circuit Tester

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Miro-Flex LED Tailer Light w/ Reflector - Brake, Tail, Turn - Submersible - Rectangular - Red

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Question:

I’ve had this product for a few years. The license plate light is out and the lights are only to turn and brake. Can you confirm this product does not have running lights?

asked by: Evan

Expert Reply:

The taillights on the Thule # TH665C Transporter Cargo Carrier should function as brake lamps. turn signals and running lamps. It sounds like you have a problem with the running lamp circuit, as the license plate lamp is on the same circuit.

I'd first test the trailer connector on the vehicle while the headlights are on. A simple circuit tester like # PTW2993 works well for this. Check the pin on the connector that's fed by the brown wire. If you're not getting power on that wire with the vehicle's headlights on, you likely have a blown fuse. Check the fuse box for the fuse that protects the trailer running lamp circuit and replace the fuse. If you don't use the trailer connector for anything other than the # TH665C cargo carrier, it's likely that a short in the harness on the carrier caused the fuse to blow.

If you do get signal on that wire, begin at the trailer connector for the cargo carrier. Find the brown wire and trace it from the connector to the taillights and the license plate lamp. Look for loose connections or broken wires and repair as necessary. If the wiring harness is in bad shape, you might be better off simply replacing the entire harness, the replacement is part # TH05254

If the wiring is good, there is a possibility that the running lamp filaments in the taillights and the filament in the license plate lamp burned out one by one without you noticing it, especially if you don't use the carrier very often. The taillight assemblies are sealed, so you can't replace the bulbs, we carry the LED replacement assemblies like # STL35RB which will draw less power than the originals and will be much brighter and will last longer. Our customers tell us this lamp is a perfect replacement for A33GB.

And for the license plate bulb, you can get the replacement 168 bulb from any auto parts store, or you could go with the # 753-2026 replacement light/plate bracket kit.