Check out this old post. You're better off powering the lights directly from the battery through a relay. I did this on my 2002 F350 CC 4x4 SB. A lot better than just splicing into the stock reverse light circuit.

https://www.ford-trucks.com/forums/3...up-lights.html

If you need a diagram, PM me and I'll try to send it. I can't seem to post it here.

 

Hey Jakebrake; I am hooking up aux back-up lights and have the outfitter switches. I am wondering whether or not I need t run a relay?Also does anyone know where I might find a wiring diagram for this app?



Just trying to get back to Bull Shoals to FISH

 

I went straight to the wire on upfitter 1 for mine and they work great, no relay as I believe there is already a relay in use with the upfitters.

 

As Trophy_23 states...no relay is needed. Just hook up to the upfitter switch wires and you are good to go! Look in the 6.0 tech folder under "Upfitter switch wiring" for all the specifics on the switches and what the current rating is for the different circuits. Good luck!

 

i just installed the upfitter swiches real easy nice and clean i also just put in back up light and wanted the same thing to be able to turn them on and off.

 

I came to ask this question. Thanks.

 

While 18ga is not ideal it should be ok for a couple of 55W lights. Lights are a resistive load so there is no inrush startup current issue. A pair of 55W lights should use about ~9A when both are on (assuming 12V as I expected these would mostly be used at idle...they would use even less if the engine was revved and the voltage rose to 13.8V).

If I remember correctly there are various sizes of these 'customer convenience' wires. 18ga would be fine as 18ga can handle about 10A safely (this is in a cable or conduit...in free air, it is closer to 15A or so). I would be sure to protect this wire with a fuse no bigger than 15A. A 10A fuse would probably OK as well but you may have nuisance blows especially if you are intending on leaving the lights on for a significant period of time. Fuses/circuit breakers are generally sized to blow at 80% of rating when that current is consumed for a significant period of time.

16ga would be perfect...you have 13A in cable or conduit and a little over 20A in free air.

Yes, these numbers are higher than many would expect if dealing with house wiring. the NFPA/NEC intentionally holds back ampacity ratings of 14ga, 12ga and 10ga wiring to have an extra safety margin in a house (some would argue it was to make the wire makers more $$$).

Bpounds: I am sure you know this already as you appear to have an electrical background but I was posting for the benefit of others.