Last updated on March 20th, 2010 at 12:16 pm
Your travel trailer or fifth wheel is broken down on the side of the road at night and you want to take your truck into town for parts or to get help. Wouldn’t it be nice if you could leave the trailer marker lights on? Since flashing lights mean caution or emergency it would be even better if you could make them flash.
I’ve seen instructions for an emergency flasher that requires you to purchase a female connector, do some soldering and wrap the lash up with electrical tape. Well, as you will see from the illustration below, this way is so easy that anyone can do it and all it takes is a heavy duty 2-pin flasher available at any auto parts store.
The key is to connect the flasher to your trailer’s umbilical plug as shown in the illustration. See how the plug is oriented with the square bump at the top. Notice the two white arrows pointing to the top two pins of the plug. The pin on the left is #4 and is the battery charging line. The right pin, #3, supplies power to the license, tail and running lights.
When you want the lights on but not flashing… we use our running lights as makeshift Christmas and party lights… just use a short length of 12 gauge wire as a jumper to light up your rig.
You may also want to read: Wiring the 7 Pole RV Tow Vehicle/Travel Trailer Umbilical Plug at RVbasics.com
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One cautionary note on this set up – depending on how your TT or 5W is wired up, when you jumper out the plug as shown, you will be supplying 12 volts to the running lights, but you may also be bypassing any fuses protecting the running light circuit. Granted there is almost always a “main” 12 volt fuse or circuit breaker right at the battery that should blow if there is a short in the running light wiring, but that would take out the whole 12 volt system
My solution was to buy an inline automotive fuse holder and use that as a jumper …..
That’s a good suggestion. Thanks.