Will Tow Bar Lighting Transfer Into Trailer Wiring of Towed Vehicle

Updated 10/21/2025 | Published 10/15/2025

Question:

I flat tow my 2020 Escape Hybrid and have the Roadmaster 4-diode wiring harness for towed vehicles installed to get the RV lights to the vehicle. Will this TE54FR get the RV signals to send on to the auxiliary lights on my bike rack which is on the back of the Escape? I did not have the factory hitch package. Im thinking that because the diode wiring is done right at the lights that the signal from the RV will bypass the connection made the TE54FR plug.

asked by: David G

Expert Reply:

Hey David, this is a great but your tow bar lighting will also transfer to the trailer wiring part # TE54FR that you referenced. So your tow vehicle's taillight circuits will make it's way to your bike rack that is connected to your towed vehicle trailer wiring connection. What bike rack do you have?

expert reply by: Jameson C

David G.

10/18/2025

I installed the TE54FR wiring kit and it works perfectly from the car's system. I then hooked up to the RV and found that the cars lights work from the RV but not the bike rack lights. It may be difficult for me to explain but I think that the flat tow wiring system that is using diodes to tie-in to the cars lighting system prevents the RV signal from going back into the car's electrical system. The RV's signal and the diodes are connected right at the light bulbs. The diodes have 2 inputs and 1 output. The RV and the car inputs on one side and the one output to the light on the other. The RV signal gets to the diode and then out to the light but never into the car's wiring. The TE54FR harness plugs into the car's wiring at a point which is before diode connection point. If I could connect the TE54FR to the output side of the diodes then I think the flat 4-pin connection would work the way I need it to. I have a Thule Easyfold XT and I attached a Curt auxiliary light system to it.

Jameson C.

10/21/2025

@DavidG that is really odd as I would assume that 12 volts on that circuit would then transfer to the trailer wiring as it would be all connected. The EasyFold doesn't normally have lights though so what light kit do you have installed on it?