03 F 150 4 flat to 7 blade RV

[johninmo]

Hello I recently purchased a 03 F150 extended cab 4WD Heritage Edition it currently has a 4 flat plug. I am mainly wanting to pull my boat to the lake which has a 5 flat. I have a 7 blade to 5 flat adapter I used on my other truck so I was wondering if I could buy a 7 blade RV plug that would plug into my existing harness or what would be the best way to go. Does the 5th wire on the 5 flat actually connect to the backup lights or the elec. brake on the 7 blade RV?
Thank for your help

 

[H20Rat]

Re: 03 F 150 4 flat to 7 blade RV

First, does your trailer have brakes? What kind of brakes? Is the 5th wire hooked up to them? Normally, in a boat trailer, the 5th wire is used for a backup solenoid. (in non-boating applications the 5th wire sometimes is for constant +12v power, there is no official standard)

In any case, the better option would be to wire the truck with 7 wire, and then convert down. I'm actually somewhat surprised the truck doesn't have that already!

 

[johninmo]

Re: 03 F 150 4 flat to 7 blade RV

my trailer does have brakes. I was told before that when you brake my tongue depresses and the brakes are applied and the 5th wire hooks into the backup lights that way when you backup they dont apply. I am unsure if this is true that is why I am asking by the way I have a 99 Skeeter ZX185C Bass boat with a single axle trailer if that helps any
Thanks