I want to install a set of backup lights on my utility trailer so that they will come on when I put the truck in reverse. I am rewiring my trailer wiring from a flat 4-wire to a 5-wire cable. I have gotten two different answers on the color coding. One site says a red wire is standard for backup lights and the other says a purple wire is to be used. I just want to be consistant so anyone who uses my trailer will be wired the same. It appears the center plug is to be used for this application but I don't know if that's a constant power source that I have to add another switch to or it is activated by the transmission reverse switch or just tied into the backup light wiring.

Any comments or suggestions will be appreciated.

 

Not too sure where the color code you are referring to is at, the big thing is having it on the correct pin assignment on the trailer tow adapter.

The flat 5 I have always know, the reverse circuit is added to the end of a flat 4 pin adapter ( other end from ground with the pin reversed ) so a flat 4 pin trailer can used used on a flat 5 pin adapter on the vehicle.

This is the best I can find for it straight away :


i only know a 4 pin & 5 pin to be flat, but that is from is a myopic view of the world from me.

 

The sites I got the wiring color codes from are:

http://www.hitchinfo.com/index.cfm?e...ntpieceid=5148

http://www.etrailer.com/faq-wiring.aspx

http://www.horsetrailerworld.com/home/wiring.asp

 

You can shoot for the wiring color if you want to, but the color of the wire has no impact on the function, the correct pin placement does.

Red to pin 5 on a flat 5 or blue or purple to a flat 5 will not matter.

Looks like the 5 pin flat is just as confused as the 6 pin round, where there are multiple variations of it floating around.

You can go the route of wiring your truck to the 5 pin flat that matches your trailer, but you have a few issues here
1. 5 pin flat is not that common of a connector overall. some still use it for some reason, most have changed to the 7 pin round, and just leave the pins dead that are not used ( trailer brakes, battery charge, etc ).
2. If you find someone that has a 5 pin flat on their truck, you will need to have them check what the operation is, the eTrailer site lists the 5th pin as brakes, you have it as reverse ??

I would think you are better off changing the trailer to a 7 pin round Trailer Tow adapter, so it is standard.
This will remove any chance of having different versions floating around like the 5 pin flat seems to have and the 6 pin round.
I have only seen 1 wiring diagram for 7 pin around, it is the same just like a 4 pin flat ( thus the reason trucks have 4 pin flat and 7 pin round only ).