5 plug trailer, 4 plug truck, how to fix
 

Just picked up my boat this weekend, has an Eagle trailer with a 5 plug system, truck I towed it home with had a 7 plug so we put a 5 plug adapter for the trip. My truck a Nissan Pathfinder has only a 4 plug system, person I bought it from said I won't be able to back it up which will cause huge issues at the ramp. Any idea's on how to remedy this.

You need to tap into the reverse lights for the 5th wire. That's what activates the lockout solenoid on the trailer and keeps the surge brakes from activating while you are reversing.

So crawl under your truck, see if you can swap out the adapter from a 4-pin to a 5-pin, or splice into your reverse lights, and splice in a 5-pin pigtail down around the hitch.

Quickest way is to remove one of your tail/reverse lights and tap the Positive (12V+) wire to the reverse bulb to send positive (12V+) to the reverse lock out solenoid when you put the truck in the reverse.

Cut off the truck's 4 wire flat and splice in a 5 wire flat connector with the 5th lead coming from the new wire you added to the reverse light.

Applying 12V+ to the 5th lead on the trailer turns on the reverse lock out solenoid, disabling your brakes while backing up. Without this, your brakes will try to engage via the surge brake coupler.

Quick fix is a C-clamp on the trailer couple restricting the surge brake coupler from sliding, but it's a hokey way of doing things.

Parts are available from your local Advance Auto or similar, or any trailer/camping joint; even Wal-Mart. Make sure you use good heat shrink connectors and heat shrink tubing on all of your connections; else they will eventually corrode given your locale. The heat shrink connectors sold at Wal-Mart are actually pretty good quality, and you can buy the wire taps and heat shrink tubing from Advance Auto or Radio Shack.

Thought you could just turn plug 180 degrees (l to r or r to l) when you wanted to go in reverse to lock out the solenoid. Mine was that way, unless they were just yanking my chain. It worked backing up a hill, unless of course brakes didn't function at all!! lol

To clarify, mine had 4 male pins and a 1 female pin. This would offset the pins when flipped.

Trailer should have a lockout pin you insert into the surge brakes that locks it so it will not bind on you backing up. Some do not have the electric solenoid so look carefully. I don't think Eagle trailers are even made anymore but I could be wrong.

Wannabe

Thanks for the help. Try to tackle it in the next few days if the weather cooperates.

My Eagle trailer has the 5 pin connector, but it also has a small hole in the tongue where you can stick a pin in and lock out the surge breaks. I don't normally use that except for moving the boat around the yard. It is very easy to splice in the 5th wire from the reverse lights.

Only some trailers have the hole for a pin; most do not.

"Turning the plug around backwards" only works if you:
1) Turn on the parking lights.
2) Your trailer ball to truck connection actually makes a good ground, which it usually does not.

Essentially, you are inserting the "5th lead" on the trailer connector into the 4th enclosed lead on the truck, which is for the parking/running lights. It's not a great solution, and still requires you to get out of the truck for another hokey solution.

If it's worth doing, it's worth doing right.

Yep, went 7-pin EOH last spring.

Googled 7 pin connector for Pathfinder and found Nissan has a plug in system but I only could find a part number for 2007 thru 2010 not 2011. Thought that might be an easier route since I already bought the 7 to 5 convertor to use on my friends truck to tow it home.

My trailer is a 5 pin. and i have the 7 pin plug with a 5 pin connection and my trailer will still lock up if i try and back up a hill....

Check the fuses on the truck. Often they are designed as such that the factory config does not power the electric brakes or reverse 12V+ without inserting a fuse.

Check to make sure you have 12V+ at the reverse pin on the truck.
Check to make sure you have 12V+ traveling all the way to the solenoid.
Check to make sure the solenoid is working. (You should hear & feel a "click" if you have your ear near it, and hand on it when someone else puts the truck in reverse.)

If you have power all the way to the solenoid, replace the solenoid. They do go bad. I always used to carry one with me.

You mght have the standard reversing solenoid. It won't bleed off the pressure in the lines. It just closes the line off. A real problem if the trailer is pushing against the truck before you put it in reverse. Such as backing up an incline or being stopped and not pulling forward a hair before going into reverse.The deluxe solenoid bleeds off all the pressure. A must fro trailers with disc brakes.

Good info will check all of these things, next time i hook up to it.