Brake Controller Recommendation for a 2013 Mercedes ML350

Question:

I would like to get a P3 for my ML350, do you have a recommendation on mounting location? Also do you have a pigtail to plug into my brake controller plug on my ML350?

asked by: Dan N

Expert Reply:

While there isn't a specific wiring harness to plug into a brake controller plug on your 2013 Mercedes ML350 the vehicle may have the Mercedes one stored somewhere or it could be available at a Mercedes dealer. Then you could wire in a brake controller such as # 90195 directly to the Mercedes harness if you know the wire functions. On a brake controller white is ground, black is 12 volt power, blue is output to the trailer brakes, and red is input from the brake switch.

If there isn't a Mercedes harness that will work then I do not recommend an in-cab brake controller because it is next to impossible to do so on a Mercedes. Instead, if the vehicle has a factory 7-Way trailer connector, I recommend the Prodigy RF, # TK94FR, which mounts on the trailer.

With this controller you may have to do a little troubleshooting if the part mounted on the trailer has a hard time communicating with the part that goes in the vehicle. If that happens there are some things you can do to get it to work:

First, if you do not see displayed what the instructions say just keep going through the steps. Sometimes, it will not display what it is supposed to but it will still work if you go through the steps to completion.

If that does not work then you can try taping off the pin in the 5 o'clock position at the back of the RF (where the trailer plugs into) using electrical tape. Then go through the installation process.

If that doesn't work you may need a 7-Way to 7-Way adapter, # C57003, which will put more load on the system and could allow the RF to pair up properly.

And if all of the above will not work then have a domestic vehicle with a functioning 7-Way parked right next to your Cayenne and pair the RF using that vehicle. Then just move the handheld unit to the Cayenne and tow the trailer with it and it will work.

expert reply by: Michael H

Jon

7/10/2020

Would the Autowbrake trailer mounted brake controller work as another option? The Prodigy RF is sold out and it seems like Autowbrake is less setup between tow vehicles?