Troubleshooting Brake Lights Not Working With Curt Wiring Harness on 2024 Toyota Grand Highlander

Question

Question:

I have installed Curt #56480 on a 2024 Grand Highlander. I have running lights and blinkers but the brake lights just blink and go off. Any ideas? Thanks

asked by: Tony

0

Expert Reply:

There isn't a lot to the installation of the # C79VV so it is likely one of two things. The first is the ground connection. Double check the ground connection and make sure it is secure on a clean, bare-metal surface.

The other possibility is that your connectors aren't all the way together. Go ahead and pull each apart and reconnect to make sure they are fully seated. If that doesn't fix the problem feel free to reach out and I will help you troubleshoot further.

UPDATE: We have updated our guide and as of April 2024 the only wiring harness confirmed to fit the 2024 Grand Highlander if you DO NOT have the tow package is the # C59236.

expert reply by: Robin H

0

Barry W.

2/17/2024

This seems to be a real problem. I've seen 3 comments now with the same issue. It's happening to me as well. I ran a direct wire from the white wire on the convertor directly to the battery. Same issue. Brakes blink and go out. Is there something on the system computer that needs to be done? Reset? "Turn on" towing? Please help. I've been trying for 3 weeks now to find the correct wiring harness and to get it working.

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Robin H.

2/20/2024

@BarryW this is just basic troubleshooting based on the information we have available. If you are having the exact same problem I would reach out to Curt and see what they say. They are generally great about testing their products but it is also possible with the limited time it has been out they didn't account for something on the vehicle that would cause this problem. That may not be the case, but it seems likely with multiple Grand Highlander owners running into this. If you're on the phone with them while standing at the vehicle they can narrow down any potential problems and help solve them.

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Bobby S.

4/14/2024

@BarryW Hey mine is doing the same. Have you found a solution?

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Barry W.

4/14/2024

@BobbyS Contacted Curt directly. They say they do not have converter that works for GH. Returned part to eTrailer. Ordered part PT725-48241 directly from toyota. Then you still need harness from under rear bumper to trailer. Thought everything was all good, but then determined that left/right and ground/running wires were "crossed". So bought waterproof splices and switched green & yellow and then also white & brown wires in the wire harness between bumper and trailer. I know my boat trailer wires are correct because I've towed with a toyota 4runner and honda pilot with factory tow packages. Seems Toyota has decided to flip wires around on the GH for some reason. I attempted to order the harness between bumper and trailer from Toyota but at the time could only be bought with the complete hitch and bumper wiring package. I've towed boat 4 times now and works great so far. Maybe Curt convertor has same issue and just needs the wire harness wires flipped as I've done. First start by testing the Ground (white) wire to be sure it is a true ground and not actually the running lights. Test this at the connection where you would plug your trailer. I made the mistake of testing the white ground inside the vehicle at the converter rather than at the actual point of plugging trailer. Why the heck can't etrailer find someone with a GH and figure this out? I hope this helps someone since it took me 5 weeks to get it sorted out.

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See All (6) Replies to Barry W. ∨

Answer 1

I recommend going with a T-Connector wiring harness for your 2023 Toyota Highlander XLE: - With Factory Tow Package #C79VV - Without Factory Tow Package #C59496 The easiest way to determine if you have the factory tow package or not is to look at…

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Answer 2

Try improving the connection of the main ground wire of the trailer wiring harness. Make sure it is attached to a clean metal surface. Or you can run all of the trailer wires back to the main ground. This is actually the ideal solution. But you can…

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Answer 3

First you will need the Curt T-Connector Vehicle Wiring Harness #C79VV to connect to the factory wiring on your 2024 Toyota Grand Highlander. This will take care of the lighting needed for the trailer which will connect through the 7-Way Kit #ETBC7.…

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Answer 4

You will want to get under the hood of your 2020 Toyota Tundra and find the 30A TOW TAIL Trailer side light fuse in the #9 position. This is what will control the power going to your 7-way way harness. This fuse is either missing, blown, or there is…

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Answer 5

It could be a tow package fuse on the vehicle. Use the owners manual to find the locations of fuses/relays related to the tow package wiring to check them and replace as needed. If the issue is not a fuse or relay then you can test the vehicle side…

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Answer 6

To add a hitch to your 2024 Toyota Grand Highlander, I recommend the Curt Trailer Hitch item #C26VV. This hitch is custom fit and bolts to your Toyota with included hardware. The Curt item #C26VV is a class III hitch with a 2" receiver. It has a…

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Answer 7

LED lights draw considerably less amperage than incandescent lights. They also run much cooler. These 2 features are why LED lights last so long. The incandescent version of #STL8RB is #ST8RB and it draws 2.5 amps for the stop/turn signal functions…

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Answer 8

The difference between the Class II and Class III hitches has to do with their Gross Trailer Weight (GTW), their Tongue Weight (TW), and their Hitch Receiver Size. Class II trailer hitch receivers have a 1-1/4 inch receiver and can be rated up to…

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Answer 9

Yes, we do. To add a hitch to your 2024 Toyota Grand Highlander, I recommend the Curt Trailer Hitch item #C26VV. This hitch is custom fit and bolts to your Toyota with included hardware. This is a class III hitch with a 2" receiver. It has a…

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Answer 10

A 4-Way trailer connector has the basic lighting functions only; running lights, left turn signal and brake lights, right turn signal and brake lights, and ground. A 7-Way has these functions and a 12 volt circuit, a circuit for electric trailer…

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Answer 11

As far as wiring for the 2024 Toyota Grand Highlander, we do have the Curt #C59236 available which is more of a universal hardwire harness. Unfortunately there are not any plug-and-play options that have been confirmed to fit as of yet (October 4,…

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Answer 12

I have attached a picture below of the Curt Hitch item #C26VV installed on a 2024 Toyota Grand Highlander. I really like this hitch because the crosstube installs behind the rear bumper leaving only the 2" receiver exposed. The Curt Hitch item…

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Troubleshooting Brake Lights Not Working With Curt Wiring Harness on 2024 Toyota Grand Highlander

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