This information applies to RVs travel trailers and fifth wheels with the 7-way flat-pin type plug. This is the most common type plug found on trailers but your trailer may have another type connector.

Your travel trailer 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 marker lights on? Since flashing lights mean caution or emergency it would be even better if you could make them flash.

(It's happened that drunk drivers have driven into the back of a vehicle parked on the roadside thinking they were following traffic. So, using flares along with flashing lights is a good idea.)

Roadside isn't the only place where having flashing lights may be useful. Suppose you're boondocking out in BLM land and need emergency assistance. Maybe you can call for help on your cell phone but how in the world can you give specific directions to your fifth wheel. Those flashing running lights out in the darkness could be the beacon emergency response people need to find you.

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 can see from the illustration above, 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 lights... you can use a short length of 12 gauge wire as a jumper to light up your rig.