Curt C56434 Wiring Harness Has No Power at 4 Way Connector

Updated 08/29/2026 | Published 08/20/2026

Question:

Trailer wiring kit quit working hooked to towmate light bar - no power to any 4-pole connector poles. RAV4 lights work OK. Believe kit is Curt C56434. Wiring kit has no fuse so suspect kit converter box. Is there a reset button anywhere?

asked by: John M

Expert Reply:

Welcome back John,

I wish there were a reset button because that would make life a whole lot easier, but the Curt # C56434 does not have one. Before blaming the converter box, I would start with the power supply to the harness. One thing worth checking is that the C56434 is a powered converter and should have a dedicated 12 volt power wire running to the RAV4's battery with an inline fuse near the battery. If you aren't seeing a fuse, I would trace that power wire because a missing, blown, or disconnected fuse could leave you with no power at the 4 way even though all of the RAV4's lights still work normally.

I would also take a really close look at the ground connection. I know it seems like a small thing, but a poor ground is one of the most common causes of trouble with these wiring harnesses. Make sure the white ground wire is securely attached to a clean, bare metal surface with no paint, rust, or corrosion between the terminal and the vehicle body.

If the fuse and battery connection look good, grab a circuit tester and check the black power wire going into the converter. You should see approximately 12 volts there. Then turn on the running lights, brakes, and turn signals one at a time and test the appropriate wires going into and coming out of the converter. If the converter has its 12 volt power supply and is receiving the proper lighting signals but nothing is coming out to the 4 way, that points to a failed converter box and the harness would need to be replaced.

When did it start acting up? Did it just all of a sudden stop lighting up or was it intermittent?

expert reply by: Heather A

Frank

8/27/2026

I had no problems that I can remember installing this wiring harness. There is a 12 volt battery in the back , I wired the harness to that two years ago and never had a problem since. ------Frank

Heather A.

8/28/2026

@Frank Awesome Frank, it's always nice to hear from someone using the product. Thanks for joining the conversation! What kind of trailer do you have?

Myron

8/27/2026

I had this harness installed on my 2024 RAV4 Prime. It has worked well. Never had any problems with the harness or the control module. Note that I didn't install it myself, so I can't speak to the ease of installation. I know the buy who installed it said it went in easily. He did hook up to the battery wiring that is in the back hatch area of the RAV4. He didn't have to run the harness all the way to the front. I think that made it easier. I will make one caveat to my happiness with the harness. The ground contact on the 4 pin harness connector that is mounted to a bracket underneath the hitch broke off about 18 months after the harness was installed. So, I had to buy a replacement connector with about 18" of wire out the backside of the connector and cut and splice the new connector in. I wasn't real pleased with the fact that the contact broke off. But, the cut and splice was an easy fix! In fairness, it could have been the mating connector from the trailer harness wasn't a great fit to this harness's 4 pin connector. I changed trailer connector out at the same time I changed out the SUV harness as well. I just know that since changing both connectors out, I haven't had any problems. It mates easy and works like a charm. I would suggest checking how easily your trailer connector mates with the harness connector before moving forward with installation. Once you know it mates easily, then I think you can move forward with installation and will be pleased with the functionality and quality of the harness.

Heather A.

8/28/2026

@Myron Thanks for sharing all of that, Myron! That’s really helpful advice, especially the part about the ground contact and making sure the two 4 way connectors mate together easily. A loose or damaged ground connection could definitely cause some frustrating issues. Big props to you for fixing the issue in the end! What kind of trailer are you towing?

Trailer T.

8/29/2026

@HeatherA, It's a lightweight 10' x 5' Lowes trailer. My RAV4 only has a 3500' towing capacity. So, I don't want a heavy duty trailer. I wish I could find the connector I replaced the OEM connector with. I think it was a Curt connector as well. But, I can't find the order email or the invoice.

Heather A.

8/29/2026

@TrailerT Ahh got ya, it is important to stay under that weight limit for sure. You purchased Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector Part # C56434 for the Rav4! I was able to find your account :)