12v Pin on 7-way Trailer Connector on 2020 Ford F350 Not Putting Out Power  

Question:

Expert Reply:

A few years ago, Ford started equipping their trucks with the so-called 'smart' trailer connectors. The 12 volt feed on the trailer connector won't supply power unless the following conditions are met:

• Ignition is on with vehicle running
• Vehicle senses that a trailer is plugged in
• The brake pedal has been pressed at least once during the current ignition cycle

I wasn't able to find how the vehicle 'knows' whether a trailer is plugged in, it could be looking for a draw from a trailer mounted battery, or the resistance from the trailer brake magnets or the draw from the trailer lighting circuits or perhaps a combination of all these.

You could try picking up an inexpensive 7-way plug like # A7WCB and wiring up the terminal for the 12V and ground to the pump and see if that creates enough draw on the correct circuits to turn on the 12V feed. You could also install a 12 volt plug and plug the pump into a power port in the vehicle.

You could also sever the wire from the vehicle feeding the 12v pin the trailer connector and run it directly to the battery through a 40A circuit breaker like # 9510. Since this would keep that pin active at all times, you might want to install a battery isolation solenoid like # PK5231201 that will shut the feed off when the ignition is off so you don't run down the battery accidently.

expert reply by: Mike L

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