Troubleshooting Freightliner with No Extra Pins on 7-Way for Brake Controller Function

Updated 06/17/2024 | Published 06/11/2024

Question:

I have an interesting one for you, we have a freightliner f106 with air brakes and we installed the P3 brake controller. Our boat trailer is req'd. to have a 7 round pin cord by the US Navy. It is a triple disk brake with a brake rite pump, So far all of the clearance lights, turn signals and brake lights function as designed. Our problem being with a 7 pin plug there is no spare pin for the brake controller, any suggestions??? Thank you

asked by: Dan T

Expert Reply:

Thanks for reaching out, Dan!

It sounds like you might need to combine the stop and turn signals for your trailering setup, because the standard 7-Way vehicle-side socket will have a pin dedicated to the brake controller signal from your Prodigy P2 # 90195.

Attached is a diagram showing what the pinout SHOULD be on your 7-Way. Let me know what functions your 7-Way pins have and I'll be more than happy to help you figure out what you need to do to get everything up and running!

expert reply by: Jon G

Wiring Pinout for Standard 7-Way Socket
(click to enlarge)

Dan T.

6/17/2024

Jon, we cannot use a RV plug, we must use a 7pin round semi type per the contract.

Jon G.

6/17/2024

@DanT If that plug is only going to be used for RVs then you'll need to rewire it so the pins match the functions that I referenced in the photo above. Aside from that, if the Navy has your hands tied with certain restrictions in your contract then you'll need to talk with them about what kind of wiggle room you have to get the plug compatible with an electric brake controller.

Dan T.

6/17/2024

@JonG There in lies the problem the trailer being pulled is NOT an RV, it is a Boat trailer is wired as a semi trailer W/O air brakes, the only difference there is between this boat trailer and a semi wired trailer is, it has electric disc brakes. So are you saying it can't be done? Isn't there a RF kit from Brakerite that makes it a stand alone?

Jon G.

6/17/2024

@DanT I apologize for the confusion in my last statement. The standard 7-Way for RVs is industry-standard across the board - even for boat trailers. I don't have a wiring schematic of a semi trailer, but to my understanding they have more functions separated out while a standard 7-Way used for RVs/boat trailers have the stop and turn signals combined. If all of the pins on your 7-Pin Round connector are being used then no, there is no physical way to make this happen aside from altering the pinout and/or using a different connector that has more pins. If your contact with the Navy has a very specific way laid out of how the 7-Pin Round connector is supposed to be wired then I have no say in how you're supposed to fix this. That's something you'll need to take up with the Navy. There used to be an RF kit as part T4835600 but that has been discontinued. It's also important to note that RF controllers plug into a 7-Way that use the industry standard 7-Way pinout so if you have a proprietary pinout you still wouldn't be able to use an RF unit.