Will My Trailer Brakes Continue To Work If The 12V Pin On The 7-Way Connector Doesn't Work?

Question:

If the 7 pin from the tow vehicle the 12 v pin does not work. Does that mean your trailer brake will not work?? Thanks

asked by: Dean G

Expert Reply:

This will depend on your brake controller first.

The Curt Echo # C51180 or similar style brake controller require the 12 v charge line circuit(1 o'clock position) to receive its power to operate the braking system. So with this type the trailer brakes will not work at all.

For a more traditional brake controller like the Tekonsha Prodigy P3 Trailer Brake Controller # 90195 it does not need the 12 v charge line to operate the trailer brakes. It receives its power from the vehicle on a different circuit and sends power out through the brake controller pin(5 o'clock position). With this system the brakes will operate as intended when connected to the 7-way.

The only issue is the charge line circuit does maintain the breakaway battery current as well. So if your trailer were to become disconnected and the battery has been depleted on the breakaway circuit, the trailer will continue to roll rather than the brakes being activated to stop the trailer.

If your vehicle came with a 7-way plug my guess is either the fuse/relays were not included from the factory or they have become damaged. You can add/replace those parts to get your power working again. If this is an add on 7-way you can run a 10 Gauge Primary Wire # 10-1-1 with a 40 Amp In-Line Circuit Breaker # 9510 to your battery to ensure that you have power running through the charge line circuit. Just remember to disconnect the trailer connector when you are not towing as this will drain your vehicle battery if it not on a ignition only circuit.