Troubleshooting P3 Brake Controller Not Connected Error on a 5 Prong Boat Trailer

Question:

Hello, I purchased a P3 brake controller and the factory harness for a 2014 Chevrolet Silverado 1500 to match with my new boat trailer which has electric over hydraulic brakes. My boat trailer has a 5 prong flat plugging into a 7 way connector which plugs directly into my factory trailer plug. I installed the new brake controller and harness on my truck and the controller is reading NO TRAILER CONNECTED. This is a new trailer with only 1foot of wire from the pig tail to the the hydraulic solenoid so I can clearly see no corrosion, no broken wires and actually took the trailer ground to bare metal so its clearly grounded good. My truck does have a factory installed brake controller but then I added the P3 and factory harness. I thought just plugging it in would bypass the system thus allowing my truck to read the trailer and making the electric over hydraulic brakes work. Do you know if there is a fuse or something I need to remove from the factory fuse box to disable the factory system to allow the after market controller to work? Are both the factory and after market clashing thus making the after market state no trailer connected? Any help or ideas would be greatly appreciated.

asked by: Louis L

Expert Reply:

Don't worry, I can help.

The reason your brake controller is reading "no trailer connected" is because the 5- to 7-way adapter you are using cannot read electric brakes. There is no 12V power or brake wire signal on a typical trailer end 5-way.

Your best bet is to add a 7-way connector to the trailer like # HS381-9000. This kit includes a 7-way, a junction box, and hardware. To complete the connection you will want to run 10 gauge wire like # 10-1-1 from the junction box to the brake actuator and another 10 gauge wire from the junction to the break away battery.

If you don't currently have a break-away battery you will need one that is properly rated for the EOH system you have in place. For example a Titan EOH system requires a 10amp hour break-away, the Hydrastar requires a 5amp, and the Dexter requires a 9amp hour break-away battery. If you tell me which actuator you have I can help you get the right break-away battery setup.

I have linked two diagrams on how to wire up the break-away battery to the Titan and the Hydrastar/Dexter as well as a Help Article on wiring for you to check out.

Let me know if you continue to have issues after this, I'd be more than happy to continue to troubleshoot this with you.