help needed with front brake light

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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jimg1au
Posts: 26
Joined: Wed Jan 31, 2018 7:25 am
model: 750 Sport
year: 1988
Location: Australia

help needed with front brake light

Post by jimg1au »

getting ready for rego and front brake light wont work
using the rear brake light come on
I have tried to see if its the switch by joining the two wires together with ignition on still not working
the real problem is I am colour blind so tracing wires is not easy
anyone had the problem of the front brake not working the stop light
brakes work fine
thanks
jim
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Derek
paso grand pooh-bah
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model: 907 I.E.
year: 1994
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Re: help needed with front brake light

Post by Derek »

The usual problem with the front brake switch is that the tiny plastic pushrod has dropped out when the lever has been removed, or the switch itself has packed up but since your stop light isn't working when the wires are joined together you can probably rule out the switch.

Of the 2 wires, one is grey/yellow and the other is just grey. Even if you are colour blind you should be able to see that one has a strip and the other doesn't. The wire with the stripe should have 12V when the ignition is on. Use a test lamp to check that it does. That wire goes straight back to the fuse box and is on the same fuse as the lights and injection (strangely the rear brake light gets it's feed from the other 15A fuse). If there is no 12V on that wire there is either a break somewhere or it has a poor connection at the fuse box (more likely). If the fuse was blown you wouldn't get lights and the engine wouldn't start.
The other wire (plain grey) goes straight to the tail light connector where it is joined by another grey wire from the rear brake light switch. Check it's connection at the tail light and it's continuity from the front brake light switch.
That's about all there is to it.
1994 907ie
2017 Supersport 939
2015 Scrambler Classic
1982 Pantah 500SL (now sold)


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jimg1au
Posts: 26
Joined: Wed Jan 31, 2018 7:25 am
model: 750 Sport
year: 1988
Location: Australia

Re: help needed with front brake light

Post by jimg1au »

A mate come over and there is power so need to trace the other wire must have a brake somewhere
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paso750
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model: 750 Paso
year: 1987
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Re: help needed with front brake light

Post by paso750 »

The usual problem with the front brake switch is that the tiny plastic pushrod has dropped out...
The Sport does not have an electrical switch at the brake master cylinder but a pressure switch located in the brake hose splitter.
Accoring to the wiring plan the colour of the wires are yellow/red and blue/black. It's interesting btw that the plan shows only one switch while the rear brake pump also has one.

However, if there is power on one wire disconnect both from the switch and measure its resistance. The switch should be open and if you apply brake pressure it should measure a short. If it doesn't the pressure switch needs to be replaced.

If you can see two tiny holes in front of the brake master cylinders reservoir you can install an electric switch which will also react quicker than the old pressure switch and it's probably also more reliable.
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Derek
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model: 907 I.E.
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Re: help needed with front brake light

Post by Derek »

Right enough. I wasn't paying attention again. :roll: I was looking at the diagram for the 907.
Colours are different but principle is the same. Yellow/red to the tall light and blue/black for 12V which looks like it is piggy-backed onto the spade connector of the horn. If there is no 12V that's the first place I'd look.
1994 907ie
2017 Supersport 939
2015 Scrambler Classic
1982 Pantah 500SL (now sold)


Scotland
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paso750
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year: 1987
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Re: help needed with front brake light

Post by paso750 »

;)
Right enough. I wasn't paying attention again. :roll: ... If there is no 12V that's the first place I'd look.
A mate come over and there is power...
jimg1au
Posts: 26
Joined: Wed Jan 31, 2018 7:25 am
model: 750 Sport
year: 1988
Location: Australia

Re: help needed with front brake light

Post by jimg1au »

I have power and when the power is put to the yellow wire at the last junction box before the tail light the light comes on thinking of just running a new wire all the way from the switch
jim
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higgy
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Re: help needed with front brake light

Post by higgy »

Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
jimg1au
Posts: 26
Joined: Wed Jan 31, 2018 7:25 am
model: 750 Sport
year: 1988
Location: Australia

Re: help needed with front brake light

Post by jimg1au »

thanks for all the help front brake light works now
jim
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