Parts Needed to Install Always-On 12V Power Circuit on 2018 Ford Super Duty

Question

Question:

I have a new 2018 F450. The 12V lead on the 7 -Way isnt working . I have a horse trailer that has interior and working flood lights that wont work because of the issue. They only work when you step on the brake, once you release the brake the lights go out. Ive taken my truck and trailer to two different trailer dealers thinking it was the trailer, however both trailer dealers said the trailer is working fine the problem is my truck. I took the truck to the dealership where I bought it, they tested it and said the 12V lead is working correctly. They said Ford designed these new trucks when you press on the break the 12V lead is powered and once you press the brake hince the trailer lights coming on then off when the brake is release the 12V terminal will be powered and work correctly, which made no sense to me. Why in the hell would you wire it that way. Ive discovered 3 other new F350 and F450 has the same issue. Have you heard of any other issues like this on the F350 and 450. Any suggestion on a fix?

asked by: Sam L

0

Expert Reply:

Ford did decide to change the operation of the 12V auxiliary power circuits on newer trucks. The fix for this annoying circumstance is easy enough.

All you need to do is bypass the existing 12V circuit with a new direct battery connection that will allow the 7-way to have active 12V power at all times, regardless of the ignition key position or operation of the brake pedal.

You will need just a few parts to accomplish this: circuit breaker # PK54540, 10-gauge wire # 10-1-1, ring terminals # DW05705-1, wire loom # 7509-10 and butt connector # 05732-2. These will let you make a direct connection to the battery + terminal and route the new power wire to the 7-way where it will connect to the 12V wire. You can refer to the linked article on wiring as needed.

expert reply by: Adam R

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