Ducati Monster Forum

Moto Board => Tech => Topic started by: Slide Panda on August 31, 2009, 12:47:20 PM

Title: Finding a bad ground?
Post by: Slide Panda on August 31, 2009, 12:47:20 PM
Here's the whole history - '00 M900s

For some time, my low fuel light comes on with no regard for the fill level of my tank.

I've had the LEDs, and a clicker type relay and a set of resistors.  This set up worked fine.  The resistors were wired in parallel with the rear signals.

Recently, I've been working out a full (4 corners) set of LED signals, and the Badlands 'Metric Flash Pro' - which functions as a flasher relay and load balancer (the function of resistors). The benefits are cleaner wiring and their electronic balancer doesn't heat up like the resistors will.

But under the new set up, all 4 signals will come on - the 'off-side' being about 60% intensity.  I've traded a couple emails with Badlands, and they suspect problems with my grounding.  Since I have that techy low fuel light, I'm thinking they are on to something.

Anyone got advice on how to track down an ailing ground on a Monster?  Aside from the low fuel light and this LED issue, everything else works as it should

Title: Re: Finding a bad ground?
Post by: Ddan on August 31, 2009, 01:47:09 PM
Quote from: yuu on August 31, 2009, 12:47:20 PM
Here's the whole history - '00 M900s

For some time, my low fuel light comes on with no regard for the fill level of my tank.

I've had the LEDs, and a clicker type relay and a set of resistors.  This set up worked fine.  The resistors were wired in parallel with the rear signals.

Recently, I've been working out a full (4 corners) set of LED signals, and the Badlands 'Metric Flash Pro' - which functions as a flasher relay and load balancer (the function of resistors). The benefits are cleaner wiring and their electronic balancer doesn't heat up like the resistors will.

But under the new set up, all 4 signals will come on - the 'off-side' being about 60% intensity.  I've traded a couple emails with Badlands, and they suspect problems with my grounding.  Since I have that techy low fuel light, I'm thinking they are on to something.

Anyone got advice on how to track down an ailing ground on a Monster?  Aside from the low fuel light and this LED issue, everything else works as it should


You are probably bleeding through the indicator light in the dash. 

(http://farm3.static.flickr.com/2136/2548076158_1001a6db79_o.gif)
Title: Re: Finding a bad ground?
Post by: Howie on September 01, 2009, 06:39:27 AM
Dan is most likely correct about needing the diodes, but do check the grounds first.  The front signals share ground with the headlight and the rear signals share ground with the tail light.  More than likely your low fuel ight problem is the $ensor in the tank.
Title: Re: Finding a bad ground?
Post by: Slide Panda on September 01, 2009, 06:51:42 AM
Badlands Dan, yes another dan suggested placing a diode in each of the lines for the signals.

Bare with me for some theorizing - what if the dash light was burnt out? IF I still had that 4 way issue would that mean that diodes up at the dash light would not be a fix after all?

And for the more electrically educated - why does everything look right when I have more resistance in the system?  It's been too long since my basic circuits class

Quote from: howie on September 01, 2009, 06:39:27 AM
Dan is most likely correct about needing the diodes, but do check the grounds first.  The front signals share ground with the headlight and the rear signals share ground with the tail light.  More than likely your low fuel ight problem is the $ensor in the tank.

Before I go plowing into my bike yet again... what neighbor hood should I be looking in, and are there any 'proper' test methodologies I should follow.
Title: Re: Finding a bad ground?
Post by: Slide Panda on September 01, 2009, 10:28:57 AM
I sent DMF Dans solution to Badlands Dan and he said it was spot on - so thanks Dan(s)
Title: Re: Finding a bad ground?
Post by: Slide Panda on September 03, 2009, 07:08:15 AM
Hey Dan, I re-wired everything last night per your diagram and the bench test worked like a charm.  It'll be a few days before I get it back on the bike - but I'm expecting it to go smoothly.  Thanks for the guidance
Title: Re: Finding a bad ground?
Post by: Ddan on September 03, 2009, 01:55:22 PM
 [thumbsup]

Like Howie said, you should still check all your grounds.