Curt 58964 Harness (not working)

[Chris874]

I'm setting up my '25 Jeep wrangler to tow behind my motorhome.

I installed the RoadMaster baseplates and also the Curt 58964 wiring harness, which lists as plug and play to power the Jeep tail lights when being towed.

The harness has connectors that goes between the Jeep rear lights and the light assemblies, plug and play, two connecters at each assembly which only can connect one way. eTrailer.com has good videos.

A standard, four wire (green, white, yellow and brown), trailer wire then goes all the front of the Jeep. This connects to a 6 pin, which in turn connects to my RV via a 7 to 6 pin cable.

I tested all the pins from the motorhome and all pins have the correct configuration.

On my Jeep, with the Curt harness installed and the Jeep in normal operation, the rear lights, turn signals all work fine.

When I connect the Jeep to my RV, with the Jeep turned off as if being dinghy towed,, I can't get any of the rear Jeep lights to work from signals/power supplied by the RV.

Thoughts. Thanks.

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[azjl#3]

Hmm, watching I’m doing curt c96jr tomorrow

I vaguely remember one odd ground wire in setup, did you ground well? Curious I have not looked are there any diodes in this? My understanding some weird feedback can happen if when brake controller hits brakes driving Jeep lights to on, hopefully it has a diod to prevent feedback into Rv.

 

[azjl#3]

Rm88400

is the brake relay part you need with the curt if you also have. Brake controller which hits the brakes.

verified with tech, it keeps Jeep from activating brake lights of Jeep driving light if Rv lights or turn signal or brakes are on, and it make Jeep work like normal if no Rv is connected. I reviewed schematic, looks simple to me it is a simple relay disconnecting Jeep brake input if Rv input is sensed.

 

[Chris874]

In my setup, I have no brake controller inside the jeep. I'm using a Patriot 3 portable brake system that works on inertia.

The RV is supplying tail lights, indicator signals to lights and brake lights and should be doing it down a leg that the Jeep is unaware of.

I believe the Curt harness has Diodes to stop any electrical feedback from the RV into the Jeep.

 

[azjl#3]

Ok, one more find off etrailer site in regards to relay kit, the issue is letting Jeep sit 5 minutes to go full shutdown mode, then, if brake lights do not come on when pedal pushed, you do not need the relay. To your specific issue, maybe a diode is bad, probably need to chase voltage with ohmmeter…. The problem is I tried brake after letting Jeep go cold no key by Jeep, sitting driver seat door closed. Brake lights do did wake wake up Jeep. But I did not sit there for 5 minutes, I’ll do that tomorrow

here is passage

The roadmasterinc.com Brake-lite Relay page does say this under ‘exceptions’, “With the engine off for five minutes, step on the brakes. If the brake lights do not illuminate, you don't need a Brake-Lite Relay. (The five-minute wait is to allow time for the 'automatic shut down' feature, which is present on some newer vehicles, to kick in.” Your site for the relay kit does too, kind of. On your store front for the relay kit, under product information, you walk through a series of questions (‘Is a Relay Required’). One of which says: “Do the brake lights on your towed car illuminate while the engine is off? No - You do not need a brake light relay. Yes - You may need a brake light relay. Continue on to the next question. The test for this is to check to see by depressing the brake pedal with the vehicle off. If you do this immediately, with the door open, then the brake light will illuminate when depressing the brake leading you to believe you need the relay kit. Well, not really because the Jeep has a sleep mode (as referenced under exceptions on the roadmasterinc.com site mentioned above). In addition to my previously mentioned drive test, an easy way to verify this is to leave the window open with the door closed and wait a few minutes for the jeep to go to sleep and then engage the brake pedal with something like a broom stick handle through the open window. The brake light does not come on when applying the brake so no relay kit is required.

 

[azjl#3]

So, as long as Jeep sits for 5 minutes after you setup brake controller and let it sit, you should not need relay.

again, I’m thinking this is not your issue

 

[azjl#3]

More info, etrailer says that 58964 does not fit 2024, I’m thinking 25 is same as 24, call etrailer and ask about what I have the c96jr

 

[Chris874]

Thanks you may have hit the nail on the head. I'm going to call eTrailer tomorrow to discuss this.

 

[Chris874]

More info, etrailer says that 58964 does not fit 2024, I’m thinking 25 is same as 24, call etrailer and ask about what I have the c96jr

Curt sent me a hand drawn diagram showing part 58964 for my '25 Jeep.

In my testing, I did not have my supplemental brake setup in the Jeep, so the Jeep brake pedal never got pressed while I was testing it.

 

[azjl#3]

Hand drawn huh?

 

[Chris874]

Hand drawn huh?

 

[azjl#3]

whats 56407? on curt website it says this is for trailer wiring, no mention of flat towing side. Or are they using that to feed the 58964 from the rv? confused.

 

[Chris874]

While having my discussion with the Curt tech, even though the RV harness 58964 comes with a 4 pin trailer wire, he told me this would not work without that additional harness, which over the phone, I couldn't understand where this would fit in the scheme of things, so he did that quick drawing and emailed it to me.

Meanwhile, I tested the 4 pin trailer connection, on the 58964 harness, and all the lights work fine on my trailer.

I have a replacement 58964 harness arriving today, so I will test that before I cut off the 4 pin connector that will be feed from a 6 pin connection to my RV and also cut off the weird Jeep trailer connector, which has green, brown, yellow wires going to what should be a standard pin trailer (female) connector.

 

[azjl#3]

I just talked with Curt tech, he said the 56407 is only for jeep to be wired to tow a trailer, does not apply to dingy or toad.

58964 or c96jr (etrailer number) is for dingy wiring. What we need to tow jeep. But...., you will need another method to stop feedback if jeep wakes up, i'm going out to test wakeup after 5 min shutdown..

etrailer said you need the roadmaster RM88400 relay. Looks easy, but you do need to cut a brake light wire coming off brake pedal, and do need to find a relay in fuse box to power it. That would keep even a jeepo which wakes up from feedback or other brake light issues while jeep is towed. If I install this I may put in a switch on that cut wire so no matter what, I can make the wire complete the circuit and would electrically delete the relay cutout..

I'm getting closer to getting the temp magnetic towed lights.... I hate cutting OEM wires under warranty. Yes I know Magnuson Moss blah blah.

 

[Chris874]

I like the idea of a toggle switch on that brake wire that needs to be cut. I wonder if it would be possible to pull the fuse for the brake pedal and achieve the same thing, i.e disabling the possible wake up.

Yes I understand the 56407 harness and really can't see the need for it as the main RV harness (58964) has a 4 pin extension for use when towing a trailer with the Jeep and this works just fine, used it this morning.

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