Ducati Monster Forum

Well I bought a used tail light from a member here and the light works and has tail and brake brightness but when I press the brakes it doesn't have a brake light just the tail light, so it's not getting brighter.

I used to have some crap CBR tail light that also didn't get brighter. I figured the problem was that there was 5 wires on that tail light and 3 wires on the bike. Also I heard monsters have trouble with the LEDs.

This is going to sound stupid but the fuse is out as well. I know that seems like the obvious problem but I switch my horn fuse and brake fuse and it didn't change anything. I will buy a new fuse tomorrow but I know that isn't the problem. Is there someone else I'm missing here?

I don't understand what kind of tail light you are having problems with. Did you buy a used stock tail light?

Yes I did. It is the OEM tail light.

It just wont get brighter when I hit the brake. Not safe... at all.

Tried contact cleaner?

Do you have a meter to test it so you can figure out if your light even triggers in the first place?

Well seeing how both the CBR tail light and the OEM Monster light both don't get brighter I would figure it has nothing to do with the light. I do no the light does get brighter cause when I touch the yellow and red cables (I think it was those two) it got brighter. I put them in the slot it says on the tail light and I even tried changing them around. Does it have something to do with a flasher switch or whatever it's called or maybe a cable?

Fuse blown?  Is my memory off or is the horn and brake light running off the same fuse?  Does your horn work?  Start by checking the fuse.  Looking is not good enough.  Use a meter or test light.  If the fuse is bad and blows when replaced you have a short and must repair that first. Then you are ready to move forward.  Simple circuit consisting of power from the fuse box, a front and rear brake light switch in series, associated wires an connectors, socket and bulb.

Check the triggers. If you have good hearing, you should be able to hear a small click when you pull the front brake lever. That click is the light trigger. There's one for the rear too but I can't hear that one click usually. Inspect those switches and if there's anything wrong with them.

I blew the fuse trying to figure out why the light didn't get brighter. I switched a couple fuses to try and see if that was it. I will try to see if it's the trigger. I can hear a click when I start the bike, is the click as loud as that trigger or no?

It doesn't get brighter when you pull the front brake or press the rear brake lever?

I had a similar problem and it turned out to be a bad micro switch.

Also, not meaning this the wrong way, but make sure you have the wires connected correctly. I've noticed there are some color variations on the wiring and you might just have them connected + to - rather than + to +.

Did you check the bulb itself?

The click you are hearing is probably the main relay.

If you locate the micro switch on the front brake lever and follow the wires down you will come to two bullet connectors.  Pull the connectors apart.  Join the two wires going to the back of the bike.  With the key on the brake light should be lit.  If so, you have a problem with the front switch.  The problem could be a bad switch or the switch may need adjustment.  An easy way to tell if the switch is adjusted is listen for the click when operating the lever.

Same with the rear, except you probably don't have connectors at the switch, so check at the brake light.  The wire for the brake light is gray and red.

Oh, the front switch is adjusted by loosening the two 1 mm. screws that hold the switch in place.  There is also a little dowel in there to activate the switch.  Don't loose that either.  Do not loose the screws, your local hardware store will not have them.  The rear switch is adjusted by loosening the lock nut and turning the switch in or out as needed.

You are having same problem as mine. I just tried to solve it few hours ago. I was successfully solved for front brake, but not yet on the rear.

First, find the "micro electronic meter" and check whether your front lever or rear lever is still functioning well. Those levers are just the "pass through" (bypass) of the electronic system. For me, I had tested with those levers and found that they are functioning well .. which means the problem must come from "wiring system" somewhere along its length.

I started with front break, I disconnected a plug under the seat at the right hand side (located on right hand side .. near the passenger footpeg and a bit above) and found that the power cable was damaged. Once fixed, tail light was functioning well when front brake on.

I haven't started fixing rear system yet 'coz I was too sleepy. But after testing the break, it looked like the break (as electronic bypass) was funcing well. It means wiring inside (of the rear system) must be damaged somewhere. I will try to look for its cause tomorrow. Hope this helps to give you some ideas ..

Like I said the bulb gets brighter when I touch the red and yellow together so I know it works.

As for all the other things posted I will have to take a look and see. I have about 45 mins until work so I will shoot for tomorrow. I appreciate the help.

Since your bulbs work and you're obviously getting the necessary voltage to the rear end, I second Howie's idea.  I yanked my front end apart to get the guages/headlamp lowered and I found that one of the little wires (right before the bullet connector) had actually broken about an inch aft of the connector going to my clutch switch (explains my starting issues).  A local guy had a simlar problem with his 999.  Those wires can't be bigger than 20-24 guage and don't weather well. 

+1

Does your horn work?

My horn did work until I moved the fuse to the tail light. Now I have tail light but not horn. I needed to ride my bike somewhere and I just wanted the light to show in case a cop passed me. I'm going to buy more fuses tomorrow.

QUESTION. So I'm getting a click from my micro switch in the brake level. Does this click mean it's working or will it still click if it's busted and can I test it before buying a new one.

No click means either the switch doesn't work or the switch is out of adjustment.  Unless the brake light is always on.  Then it may mean the dowel fell out or the switch is out of adjustment or broken.  A click means it is in adjustment and...well...it clicks.  It is a simple normally open switch.  Hands off lever an ohmmeter should read infinity.  Lever squeezed, the ohmmeter should read 0.  Closed circuit, light goes on, open circuit , light goes off.

Every piece of info I look at shows all carbie monsters using the same fuse for brake light and horn.  This is fuse 5.  Turn indicators, warning lights, taillights and instrument panel lights are fuse 4.

Maybe your brake light is always on and that is why it does not get brighter when you use the brake. Somehow, sometimes people get the bulb in backwards.  Another possibility is the wires are on the socket backwards.

The brake light circuit is one of the simplest circuits known to man.  Power from fuse box.  Two switches in parallel.  Associated wires, connectors and socket.  Ground wire.  that is it. 

If you keep blowing fuses there is a short.