tail light doesn't get brighter when brake is pressed

So I just picked up this new tail light from Dennis Kirk and was super excited about how well it would mount up to my back fender. Then I wired it up and was severely disappointed with the results. At first I thought it wasn't getting any brighter at all when I would squeeze the brake, but then I noticed an almost imperceptible brightening that was in fact happening, however small and impotent it may be. So I'm trying to figure out why this unfortunate shitiness has occurred, and here are my three possible theories:

1) This particular product is just a piece of crap, and I need to stop being cheap and buy something better. The box did say it was "not DOT approved" and "only for use on show bikes and restoration projects". I feel like it should still have the capacity to brighten with the brakes though.

2) I just happened to get a defective one and if I exchange it for another it will work fine.

3) Something to do with my bike being old and the light being new, meaning I would need to update a relay or something somewhere else to make it work right. Although I did make sure that it is a regular bulb light and not an LED since I know that conversion requires some additional work.


If anyone has had a similar situation occur or knows what might be going on some insight would be greatly appreciated.

 

Maybe it's just me, but this doesn't sound good. It would be nice if the website said something to that effect.

 

I would go with your #1 guess. If its not dot approved I would send it back the add failed to mention that, and the next time you see something cool that says DENNIS KIRK on it will be a piece of crap to.

 

It's probably not DoT approved because it's not BIG ENOUGH.

You probably just wired it up backward, so when the "taillight" is on, it's the (bright) brake filament, and the brake is lighting the "dim" (taillight) filament.

Pop the bulb out, and see what's in it. Is it an 1157, or a lower-watt substitute?

 

Well if it said, "Not DOT approved and for show use ONLY", why did you think it would work for a street legal bike? It's not for use on the road, DUH.
Dennis Kirk does sell quality products, I have alot of their parts on both of my bikes and know it first hand. You just bought a cheap show version of the real thing is all. Do not expect it to work like you want it to!!!
It also possible that the lense dispertion is not like the DOT approved version, meaning, the lense has deflectors that spread the light out so to speak and make it look alot brighter with just one bulb.
Those "cats eye" tail lights may look cool, but are very small to people driving behind you. I see them (other models but same shape) on bikes and notice they don't really give off alot of light when applying the brakes, unless they are the LED version, which are much brighter.
Just look at brake lights on various vehicles while driving down the road. There are alot of them I never likes just because of the design of the brakelight size and lense configuration. And would surely never use them on my bike for safety reasons. That's why I like the LED lights (the good quality made ones) because of the fact that they are alot brighter and less apt to get rear ended.
Some of the after market stuff may look cool, but at what cost to your safety? Throw that light in the garbage (or hang it on the shop wall for future referrence) and get a good one.