I am trying to install some back-up lights on my truck and need help finding a good power source. I tied my power into the reverse light on the driver's side at the wiring harness, but blew 3 fuses and decided to seek some professional shade tree help before I blow or burn something expensive up. I don't really want a switch to turn them on independently, just when in reverse. Any help finding the main reverse light power source and possibly a picture would be great. Thanks Guys and Gals.

 

do you have a relay between the lights and power source ?
it should have come with your kit and should relieve any fuse problems...

 

I usually hook them up to the battery & control with a switch. This way you can use them for additional lighting if you're camping or loading a trailer..

Good Luck,

Russ

 

You can hook your reverse lights to the wire that goes to the center terminal of your 7 way trailer plug. This is a seperate reverse feed for back up lights on a trailer. It is on it's own fuse in the box under the hood. If you don't have the plug you should have the harness bundle and the tag on it will tell you the wire color.

 

What type of lights are you installing? The wattage of the lights will also dictate what size wire and fuses you install. I have seen most people use some sort of fog lamp for additional rear lighting. Fog lights are typically 55 watts each. 2 lights at 55 watts each = 110 watts total. 110 watts / 12 volts = 9.2 amps. You need to size your wire to the load on the circuit. Although 18 gauge wire is rated to handle this load, the length of the run (guesstimate 25' from battery to light) will offer more resistance. The voltage drop on 18 gauge wire over this length is 1.5 volts. Larger wire offers less resistance, but also will cost more. I would think 12 guage is the minimum I would run, or maybe even 10 guage. 12 and 10 gauge wire will have 1 and 0.6 volt drop respectively.

I would also agree with jdadamsjr about utilizing a relay. This will allow you to run a smaller gauge wire into the cab of the truck to control the relay while the larger gauge wire handles the amperage of the lights. I like to run a 3 position switch controlling my reverse light relay. I use down position for lights on with factory reverse lights, center position for off, and the up position for lights on manually. Be sure to use a properly rated fuse or circuit breaker as close to the battery as possible. Also use grommets when running wire through openings in metal.

 

Thanks Guys
I am running 10gauge wires. Both lights are 55w. All I did was mount them to the hitch cross bar, wired both lights together and grounded them to the hitch. I then spliced directly into the drivers side reverse light wire with the positive side of my harness. I guess I will try to put a relay in this afternoon to see if that helps. I did not want to run all the way to the battery or drill any holes in the cab for a switch, but I might just do that.

 

You probably don't have to drill any holes into the cab. You should be able to fit it in through an existing hole in the firewall that is not used and plugged. I think some people installing boost and pyro gauges can give some input on where they run their lines.

 

A word of caution. You may be using 10 gauge wire between the lights and to where you spliced into the reverse light, but the factory wire loom is most likely using a smaller wire. This COULD cause the factory wire to become overloaded, get hot, and possibly short out. I'm sure there are plenty of people hooking up lights in this fashion without problems. Reverse lights are generally not on for long periods of time, so the wire may not experience overheating and it should blow the fuse before it become a problem. The voltage drop I described before is lost in the wire and is converted to heat. I would just hate for you to burn up your factory wiring, that could cost some serious money to replace.

 

There's a post in the 6.0 forum about 4 wires that pass through the firewall which are cut off. They are there for truck upfitters to use so they don't have to drill through the firewall. Hope this helps.