Reverse Light Short?

Got some specs on the lights which should be accurate, They are 12V 50w 3.9Amps So i should be good. Going to leave them unhooked and eliminate them as the cause of a blown fuse if it happens again.

So i un hooked the dock lights and was still having issues with this dang fuse blowing. Looks like it might have been loose bulbs in the socket. I got them in nice and tight now and reverse lights continued to work. next i hooked up the dock lights and they continued to work so hopefully no more problems. Although i may still grab that relay device posted above and hook them up using that. After doing some math the bulbs appear to be 50w each and draw 6.9volts each. so according to the online calculator they each run around 7amps... Now they are 12v lights so i don't know why it reads only 6.9V unless its because combined they are drawing 12V? I have them running for a good hour last night on a 10amp fuse so i don't think they can be drawing almost 15amps combined or it would have blown right away correct?

So after i rewired the docking lights and tied them into the revers lights everything appeared to be working then i noticed it was still blowing the fuse. I have still left the trailer wiring disconnected. So I'm going to splice in some quick connects and leave the docking lights un hooked to see if thats the cause, which I'm assuming its drawing too much. Then I'm going to wire it like suggested above to ensure and even load.

Ya i was basically trying to use the dock light as the test light but that wasn't working out lol.

Seriously though thanks for all the help guys you rock!

Electrons are color blind and don't care what wire you use. Using a test light really takes the guess work out of it as a go/no go test. Meters can fool even very experienced techs.

The holiday rambler doesn't have the 7 pin. It has its own 5 Pin rectangular connector under the chassis which then goes to the actual trailer plug where its converted from 5 pin to the usual 4 pin. Or thats how it was. I was testing it all wrong, i went and picked up a test light and the wire that was labeled as reverse in fact was triggered by reserve only. Got everything re wired and cleaned up nicely under there and it works and looks great now :) The 5 pin wires on the holiday rambler are as following: BRN(marker), GRN(right turn/brake), GRY(backup), YEL(left turn/brake), WHT(ground) so i just pulled off the Gray(reverse) and White(ground) and walla

If you look at the picture below, you will see that the 7 pin connector really doesn't have a "reverse light" pin. It has an auxiliary pin that CAN be hooked to the reverse light. You will have to look elsewhere for your reverse light hot wire unless your manufacturer used that as the reverse light.

Here is a question. So i pulled the dock light wires to start fresh. While testing the trailer plug wires to pull my 12V for the lights it seemed that the wire that feeds reverse to the trailer lights according to the wire diagram for the rv has 12V whether its in R or not? Shouldn't that wire only have power while the rv in in reverse if thats intact the reverse feed wire? And when testing the dock lights were way brighter on all other wires than that one..

Bobbo wrote:
That is just a junction box for connecting the wires. He still has to pull wire and stay under the fuse rating.

I should have elaborated. When a junction box is used to manifold rear lights, the color codes allow someone to go directly and quickly to a circuit in question and eliminate an offending circuit or lamp in seconds.

I use 7-wire TTMA cord to connect front to rear in a motorhome. Sheathed inside 3/4" heater hose. In the front, all signals originate in a bank of TYCO (Bosch) Relays, connected to 20 amp auto-reset circuit breakers. A master 80 amp breaker protects the battery 8 gauge wire that feeds the relays.

You are fine with that setup. Keep in mind if your fuse blows when you hit reverse there is a problem in the docking lights. Your backup light should draw about 2 amps and the docking lights may draw 5 or so.