I want to add some 55 watt cheapie halogen lights mounted below my back bumper for extra lighting for those too dark situations, and I'm wondering if it's possible to buy a 4 prong wiring harness to plug into the trailer connector and use that as the power source instead of running wires the length of my rig. Will it fry my electrical system if I do this? Or should I just bite the bullet and install as directed? Yeah I did a search but didn't really find the situation I've come up with.

Thanks in advance for any help with this!

 

bump? bueller? bueller?

 

A four prong wiring harness doesnt have the reverse wire in it. Just hot, brake, left, right.

Now the 7 prong does. But I really would advise even pulling 10A (I am unfamiliar with how much current can flow through that plug) that you run through a relay and wire it correctly (fused wires the entire length).

 

I agree with Low e Red, 110 watts of halogen power is alot for the lighting circuit unless you use a relay.

 

Trailer Tow install directions show the max on the reversing circuit max draw is 5A, and 2 x 55 W light are 9.1 A total draw at 12 V. Fused to 80% rule, makes the fuse that should be installed 15 A ( closest fuse to what you would need ).

If you want to do this, you need to run some 14 AWG cord set back there ( SO or SOJ works or auto wire that instead of 90* C rated is 105*C rated ) with a relay to drive the lights.

 

you can pick up the signal wire from one of the tail lights, wont hurt factory wiring as long as you keep it to signal for relay only...

I agree, you need to run a power wire (battery -> down the frame rail -> rear of truck)

 

I'm not much of a wiring guru but quick to learn. Signal to relay? I can splice the backup as the signal through a relay in usage as the switch and run the power straight from the battery? I've found some diagrams online and was wondering how I'd be able to use that as the on/off.

oh yeah, thanks for the replys guys. greatly appreciated

 

do you want them to come on by a switch or by you putting it in reverse?

 

putting it in reverse. really don't need them by switch, though i can wire that if necessary.

 

Here is a diagram that has both the on with a switch, and on with reverse.

If you only want them on with reverse, obviously leave that part out.

 

I just put a pair of tractor type sealed beam lamps on the back of my truck. I used the power wire for the subwoofer (which I don't have and don't plan on getting) to power them. It is a fused 25 amp circuit and can be found conveniently behind the drivers seat under the floormat in my Reg cab XL. I ran a trigger wire from the radio to that location, and put a relay in back there. The power wire goes out through the floor through the grommet that's already there and back to the lights.
I put a lighted switch in the small oval panel, right beside the cigarette lighter.
Works for me. Lights are inactive with key off, which is what I wanted to prevent accidentally leaving them on.
Can post pics if someone can tell me how.

 

I would suggest that you put them on a switch rather than wiring them into the reverse lights or using the trailer plug-in!!!!

I use mine all the time to hook up, unhook, and load trailers at night and if you have them wired into you reverse lights, or on the trailer plug-in, you would not be able to do any of that. Also they are very useful when trying to pull a trailer into a tight spot or even back up with one. Also they are irreplacable for off-roading, make backing up and hooking up straps and suck a breeze. Also nice for work lighting behind truck.

these are just a few things I have noticed myself using them for and couldn't be happier with my install.

I put a lighted LED switch on my XLT center console in the very front above that little storage space, you cant even see the switches when mounted there(I have a few there). Plus there are already holes in the floor when you pull the console out and it was very easy, a little time consuming but well worth it to have them out of sight, plus...no drilling into dash!!!

here is a thread i started a while back with a few pics.
https://www.f150online.com/forums/ot...ar-lights.html