Troubleshooting Curt 56106 Converter for 2014 Toyota Sienna

Updated 09/22/2025 | Published 10/24/2017

Question:

I have a Curt 56106 powered converter installed on 2014 Toyota Sienna. Worked worked well for about 3 years but now I am getting no brake/turn signal output on the vehicle side of the 4 flat connector on the green and yellow wired holes. I see some voltage on the brown wire with running lights on, and fluctuating voltage on the brown if I activate turn signal. Voltage pulses between two readings, both well above zero. I was alone so I did not test voltage when braking. With my trailer with LED lights connected I see a very faint glow all of the time even without running lights turned on, and the LEDs pulse very faintly if the turn signal is on. I checked fuse on power takeoff at battery and it was not blown. I also jumpered ground wire along trailer since it is a Karavan and has 2 piece frame, just to see if that would help, but it didn't. I also tried incandescent lights and those did not glow at all. I also exposed converter box ground and it looked pristine/no corrosion. Any ideas on what the issue might be? Bad converter?

asked by: Larry T

Expert Reply:

Thank you for your detailed explanation of the issue and what you have already attempted. Often when you are not getting a signal to the green and yellow wires it is an indication of an issue with the ground connection, even though you did the appropriate by jumpering your ground due to the two-piece frame. You seem thorough enough that it's possible you have already done this, but if not then check your ground connections, ensuing they are secure and attached to bare metal that is clean and free of paint, dirt or corrosion.

Another thing you'll want to do is to go over your wires and make sure there are no bare wires touching and inspect closely for any crimped, frayed, or otherwise damaged wiring that may be causing the issue. It is also possible, as you mentioned, that the # C56106 harness simply shorted out and you would need a replacement. I have added a link to an article on troubleshooting 4-way wiring for you which may also be helpful.

expert reply by: Kyle S

Steve R.

9/7/2025

Hello-I have a 2014 Toyota Sienna with a Tekonsha wiring kit I installed and the trailer lights do not work. When I turn on the headlights, the brake lights come on the trailer, in auto light mode, no trailer lights work. I put the ground onto the metal structure that holds the jack, just like in the installation video. I sanded off the black paint to have bare metal. That didn't change anything. It looks like I have power to the unit, the trailer lights work with another vehicle. Any ideas? Thanks

Robin H.

9/9/2025

@SteveR I would test the power going into and out of the converter box. It sounds like that could be the issue if your ground is good. If you have power going in but not coming out that is a good indicator that is the problem.

Steve R.

9/22/2025

@RobinH Looks like I don't have any power coming out of the converter box. Thanks for the help.