DCC Tail light problems

I am having with my dime city tail light I just bought. When front light is turned on, no rear running lights are present nor is the license plate light. When I press the front brake, the brake light and license plate light up. The light has three wires, yellow, black and red. looks like yellow is the ground. I have a 1977 kz900 and have 5 wires in the rear but know that three go to the tail light...black/yellow (ground), red (brake), and blue.

Can anybody shed some light, no pun intended, on this?

Here is my DCC light
http://www.dimecitycycles.com/vintage-cafe-racer-caferacer-bobber-brat-chopper-custom-motorcycle-lighting-parts-thin-smoked-led-cats-eye-taillight-225-1005sm.html

Also need to note that the lights in my gage cluster do not light up anymore either. Or at least my speedo and tach. Think I may have blown a fuse?

The black wire on the tail light should be ground.

Not sure one the red/yellow. One should be tail light + licence plate light and the other should be brake light.

I believe you are correct on the bikes 3 factory wires. Blue is definitely running lights (tail light + plate light) - in fact it is the blue wire circuit that also provides backlight for your tach and speedo.

It sounds to me like you have a couple of the wires connected improperly. Your tail and plate light are coming on when you hit the brakes - so you need to switch whatever you have the bike's red wire connected to currently to the other wire on the DCC light.

The reason your speedo and tach are not lighting up is probably because you've grounded the blue wire - my guess is that you have it connected to black of the DCC light?

But grounding it might have also blown a fuse too. So you should check the fuses. I installed a cheap aftermarket tail light a few years ago. Every time I hit the brakes it would blow a fuse. I added some rubber isolators to separate the light from the fender and that fixed it. But I also had to add a little bit under the license plate too to make sure the plate didn't touch the fender either.

Thanks diggerdanh, little update...
My gauge lights weren't working because I had the blue wire hooked up to the DCC black ground. I switched some wires around...

(DCC tail light) Black is connected to the bikes Black/yellow wire
(DCC tail light) Red is connected to the bikes Blue wire
(DCC tail light) Yellow is connected to the bikes Red wire

Now my gauge lights will work but I am still having the same problems with the tail light. No lights until I press the brake. Yes I have switched the Red and Yellow wires around to check and see if that works and it does not. It did blow a fuse, so I replaced one as well.

You have a spare battery?

Test the light off of the bike. Put the black wire on the negative terminal and then touch the other wires to the positive terminal, in turn.

I do not have a spare battery...No matter the orientation of the wires, besides keeping black on black, it makes no difference. I still have no running lights and my fuse will break as soon as I press the front brake. Even with a blown fuse the tail light will light up when I press the brake.

Does this mean I have a short coming from my front brake wires? I'm not the best At this nor do I try to act like I am. If I take my multimeter and leave one end on the negative battery terminal would I start poking around with the other end of the multimeter to try and find where the short is?

Got an email from DCC that their wiring is as follows...
Yellow: ground
Black : running
Red : brake
At this point I have wired as so and blew a fuse. So I must have a short somewhere.

If you're blowing fuses, you are grounding out somewhere. You will need to trace your entire harness back until you find the break in the wires. Is it the original harness on the bike?

Yes it is the original harness.

So blowing a fuse on the tail light or only when the brake is pressed? Do you still blow a fuse if the tail light is not hooked up?

I am blowing a fuse only when the front brake is pressed. I do not blow a fuse when the tail light is not hooked up.

OK...I was looking at the wiring diagram, had my fuse box open, and was reading my Ohms. I put a new fuse in the third slot, for the Tail, and placed the key in the ignition, turned it to on. I then turned the right hand control to Run and the fuse blew. I did not grab the brake at all, so all along when I thought it blew because I grabbed the brake I was wrong.

So tracing everything on the wiring diagram, the third fuse leads me to the dimmer switch and the headlight switch. So I'm confused...looking at the wiring diagram it looks like none of the fuses are connected with the tail lights, so I don't know why it will not illuminate in the "running light" mode. And why do my gauge lights not work when the third "Tail" fuse blows but the second fuse is still working just fine.

Another issue is that you have the wrong style fuses in there. You are using too long a fuse. There are smaller, correct ones.

The correct one have a metric size and are shorter.

Looking at the wiring diagram you posted compared to the DCC email you should have it wired..

Bike Blue to Tail Light Red
Bike Red to Tail Light Black
Bike Yellow/Black (I think, hard to tell on my laptop) to Tail Light Yellow

One thing you can check is to see if the Red/Black wires on the tail light are going to ground, just take the bulbs out and measure between the wire and the negative terminal on the battery. With everything disconnected and bulbs out this "should" be an open circuit.
And a foolish one... what size fuse are you using?

Cheers

That is exactly how I have it wired up. And thanks for the bit of the fuses. I will get rid of those and pick some of the right size up today.

Which fuse did you blow in post #4 when the gauge lights were working?

One thing I notice is that the bottom fuse in block is actually the middle fuse in the diagram so the gauge lights not working makes sense with the fuse that is blowing.

I know, strange isn't it. It has always been the third fuse that blows. Which is one reason I have been confused after looking at the wiring diagram, it just doesn't seem to fit...

Yeah this is a head scratcher..

It seems like you have a chaffed wire somewhere, maybe making partial contact so the fuse doesn't blow without a light?
You could try to measure the circuit with the light out of if, little bit of a pain but if you put the fuse in so its standing upright and only contacting one side of the holder you could put a meter in line to measure the amps on the circuit. Alternately if you have a test light or spare light you could wire it in place of the tail light to see if the fuse still blows.

Another random thought, what is your battery voltage?