Hey guys,
So i have installed a new taillight. The flashers on integ,  rated. Everything works great. The flashers , front brake wprk flawlessly  ... BUT the back brake has to be fully engaged for the light to go on. Anything less and it will not light up.

So my question is. . Is this normal? If not does anybody know a fix??

Amanda,
     This is just a wild guess, from having diagnosed many trailer wiring issues in the past, but could it be a ground issue? Not knowing how your pod is wired, I could not say for sure, unless this a common issue even with a stock GS. If some daisy chaining was done inside the pod somehow (although thinking about it I wouldn't know why, but I have seen stranger things) then the flasher may not have a ground until the brake light circuit is completed.

Some diagnostic step to take would be to find out if it is the new light, or the bike. Hook up the old factory stuff if you have it and see if everything works correctly. If so, the pod is the issue, if not, the bike's circuits are the issue and you can narrow from there.

If the pod has the wiring separated and no chaining, then the bike is the issue and you will need to start testing wires for shorts or breaks. You may need a wiring diagram for this.

Look by the rear master cylinder for the brake light switch ( I'm not 100% sure where it is on a GS). That switch needs adjusted.

The switch needs adjusting and it's MUCH easier to first remove the 2 Number 8 bolts then removing the entire assembly......easy access.
http://www.partzilla.com/parts/search/Suzuki/Motorcycle/2005/GS500F/FOOTREST/parts.html

Wow! I apologize for my earlier response. I misread your question. I thought you said the flasher on the rear would only work when the brake was applied fully. My mistake, I had just woken from a mid day nap. Gotta watch us groggy old farts LOL.

Once you have removed the heel guard you can wiggle and lift the rear brake switch up a little and wind the plastic nut down so it lifts the switch higher in the mount....

Do it bit by bit and test for your ideal desired position!

Oh yeah...right side near brake cylinder and heel guard!