Harley's kit does just that. I have one in my garage that I am not using.
I run one from Badlands that lights my turn as running lights as well as brake lights. With my Led's my bike glows at night.
This is just my running lights NOT brake lights...

 

I have the HD all into one (Blinkers-Brake-Turn Signal) Module and it works Great

 

The HD module works great if you want your rear lights to stay on as running lights. It is true they still work as brake and signal lights but when they come on it is a change in intensity and that is all. If you want them to do all the same functions but come on as a brake light and not be lit until you need them you can install the module but you need to splice some wires coming from the module. You can do a search on here for the schematic. It takes about 20 minutes to cut and solder but it works great. Mine now work as signals, and brake lights. I wasn't interested in the running part of it as I would much rather them all light up when they're needed.

https://www.hdforums.com/forum/touri...rsion-kit.html

 

This is my set up. The Rear is all leds. The three led in the lower fender was converted to the Brake / run feature. The Turn signals to Run / Brake / Turn. Air Wing saddle bag bars with lights run / brake. Bottom of tour pak sides wrap to rear as run only. Air Wing Rack for Tour Pak brake only. The Non brake picture does not show clearly the run light set up. Turn signals are run also as well as the 3 fender leds.

 

https://www.hdforums.com/forum/touri...ee-me-now.html

Here are the light mod's that I've done.

 

i have used the brake/ts module from harley for my last four harleys. it's great, because with a dyna for example, you got one tail light bulb, if it burns out or vibrates itself to death, you're a candidate for getting run into. nomenclature for the part is "auxiliary brake light/running light/turn signal conversion kit". for your 07 roadking it is harleys part number 69461-06A and you can find a description in your 09 harley parts and accessories catalog on page 657, which is in the multi fit section. they work great. i have a similar unit on my 08 streetglide. the only difference being that mine has the bullet style turn signals rather than the lolipop ones you've got on your roadking. They list for $57.95, and are a huge improvement in nighttime visibility, as well as being seen much more in the daytime too.

 

Being the cheapass that I am, I just popped an 1157 socket in each side. Did both sides for $7.

 

Can you guys see this picture? I can't see most of the pitures you guys posted on this thread.

I'm thinking of adding one more light in the cut-out area of my top box. Like the third brake light on a car. You need as much protection as you can get from the texters...

 

The turn signal/brake light/marker light conversion I just installed is an improvement in my opinion. The amber lens as turn signals only are more noticeable than the Red turn signal lens but I'm more interested in having more lights on the rear than I am about which color the lens are.
Now I want to convert the tour-pak brake lights to turn signals also.

 

I have the Biketronics unit on mine, it adds brake to the turn signals without making them part of the running lights. I like it better than the HD unit because of this. As an earlier post said, when you have run/brake/turn it's just a matter of intensity and I want there to be as big a difference as possible when I brake. In my mind it is the most noticeable option.