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Discussion Starter #1 (Edited)
Hello,

My beloved Ducati has let me down for the first time since I bought her this morning. Had a whole weekend planned with buddies riding to a bike show and then carving some mountain roads. I'm stuck at home and everyone else is having fun....Oh yes I'm the only one with a Ducati!:mad:

Did a search and found a couple of threads concerning this issue. Mine seems to have a different cause. When I apply either front or rear brake both filaments seem to get a little brighter.(another verification switches are ok) I have checked both brake switches with a meter and both are working fine. I have traced the issue to the + wires that go to the actual 1157 bulb. I have checked the repair manual wiring diagram. From what I can see the yellow wire seems to be powering both filaments and the grey/red wire has no power at all. The yellow is supposed to be connected to brake switches. When I apply either brake both filaments get a little brighter. I'm suspecting a fault with the bulb but have no spares to verify. I'm going to run to the parts store to get some spares later.

Any ideas of what is going on here? I'm still way too upset to think straight and my toe is still sore from kicking my rear tire really hard earlier!:mad:
 

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stuck on . . .

M5zealot,

As I am sure you know, when the key is on, one filament is on, which is the rear tail light. When you use either front or rear brake lever, then the other filament comes on, which is the brake light. Does your horn & turn signals work properly? The yellow wire, the tail light, also runs the instrument lights. The gray w/ red wire, the brake light, comes from the f & r brake switches. The black wire at the rear, is the ground for the rear turn signals, also. Check fuses, sometimes they look o.k., but are not, they get old, too. Corrosion can build up on the contacts over time. Replace if in doubt. Bad ground at the rear connector? Clean all the points where a ground connection is made to the frame. Corrosion again. Bulb socket in good shape w/ no corrosion?

Fred
 

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Discussion Starter #3
solved

Well it was nice to see everyone tripped over each other to help out! :p

I'm going to update the post because I'm sure it will help someone else down the road.

If you ever get your brake light stuck on.....DO NOT do ANY electical troubleshooting with wires, fuses or pressure switches just yet. You will waste your time and pull whatever hair you have left.

Try changing the bulb to a new one! This solved my problem. I spend half a day testing and tracing all kinds of diagrams when the problem was just a fautly bulb! I have never in my 30 years of wrenching ever had an 1157 dual filament bulb do this! It was a cheap Sylvania brand from Kragen's which I acutually just replaced two weeks ago. So I'm going to try another brand before assuming there is an electrical gremlin in my brake light circuitry. My common sense and above average logic didn't suspect the bulb initially since it was working. Duh. Bulbs either light up or they don't right? :D

SHAME ON ME FOR BLAMING THE DUC!
 

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Discussion Starter #4
Thanks for you response Fred, sorry I didn't see it until after I posted mine. Please tell me you were going to suggest changing the bulb next? ;)

M5zealot,

As I am sure you know, when the key is on, one filament is on, which is the rear tail light. When you use either front or rear brake lever, then the other filament comes on, which is the brake light. Does your horn & turn signals work properly? The yellow wire, the tail light, also runs the instrument lights. The black wire at the rear, is the ground for the rear turn signals, also. Check fuses, sometimes they look o.k., but are not, they get old, too. Corrosion can build up on the contacts over time. Replace if in doubt. Bad ground at the rear connector? Clean all the points where a ground connection is made to the frame. Corrosion again. Bulb socket in good shape w/ no corrosion?

Fred
 

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stuck on . . .

Change the bulb.

Fred
 

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Hello,

My beloved Ducati has let me down for the first time since I bought her this morning. Had a whole weekend planned with buddies riding to a bike show and then carving some mountain roads. I'm stuck at home and everyone else is having fun....Oh yes I'm the only one with a Ducati!:mad:

:mad:
I would have said "EF IT" and went on my ride anyway!!;)

(Hopefully somebody would have had a spare bulb!!)
 

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Discussion Starter #7
I would have said "EF IT" and went on my ride anyway!!;)

(Hopefully somebody would have had a spare bulb!!)
Well, that would have been dangerous since the brake light was stuck on..... I would have had to use hand signals to let them know I was stopping or slowing down! :D
 

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Well, that would have been dangerous since the brake light was stuck on..... I would have had to use hand signals to let them know I was stopping or slowing down! :D
There's no tail lights on race bikes. It would have kept your buddies on their toes!!:)
 

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Do you ever think - I wish I never posted this?

Me, I would have taken out the bulb, then told my buddies the "truth", just take care because I have just done the Keith Code Cali Superbike School where the first training sessions are no brakes/throttle control only and I am going to hone this today.

Also, when we ride, we look at what each others bikes are doing, not what the brake light says, as this is just on or off, not how hard or soft.
 

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The switch

My 93 900ss was doing the same thing. I found that one screw for the brake light switch on the handle bar was missing causing the switch to pivot slightly. Even after replacing the screw I had to make sure the switch was in just the right spot for it to work (switch lining up with the plunder).
 
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