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twinpot

Neutral light failure

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twinpot

Any one had the neutral light fail?  Fitted a new switch but light still won’t come on.  Any ideas please?

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Richlybow

Yep... failed on my 750x.. bought a new switch to fit first. if that isnt the problem ill have to trace further up the chain. Pain in the ass.

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embee
Posted (edited)

Connectors.

There have been one or two issues with the connectors onto the instrument panel. Remove, spray with contact cleaner, refit (maybe fit/remove a couple of times to clean the contacts).

I don't know if there are any other connectors between the switch and lamp.

On the 700 the switch has one wire from the lamp and switches it to ground (earth). If you take the wire off the switch and physically ground it the lamp should come on  (bike in neutral and ignition on but not running is safest). If it doesn't then you probably have a connection issue. I don't know if the lamp is a filament or LED? If it's filament it's possible it has just failed, if it's LED it's unlikely.

If you check the voltage at the wire when not connected to the switch it should be +12V relative to earth (same conditions as above) if it is a filament, may not be if it is LED. If you don't measure any voltage there it could indicate a problem.

The Lg wire from the switch to instrument pack also goes off to the engine ECU, so some other effects may go on depending on the circuitry in the ECU. If the bike is in neutral you can't do any harm with testing this wire, it will either be isolated or grounded when connected, so either condition is safe.

5aa67cab830ab_neutralswitchNC.jpg.ee9ee0763fa32549f63842eeda59ab12.jpg

Edited by embee
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Richlybow
19 minutes ago, embee said:

Embee,

if the bike starts in neutral, would it be reasonable to assume that the neutral switch is functioning and sending a message to the ECU that the bike is in fact in neutral?

 

 

 

 

Connectors.

There have been one or two issues with the connectors onto the instrument panel. Remove, spray with contact cleaner, refit (maybe fit/remove a couple of times to clean the contacts).

I don't know if there are any other connectors between the switch and lamp.

On the 700 the switch has one wire from the lamp and switches it to ground (earth). If you take the wire off the switch and physically ground it the lamp should come on  (bike in neutral and ignition on but not running is safest). If it doesn't then you probably have a connection issue. I don't know if the lamp is a filament or LED? If it's filament it's possible it has just failed, if it's LED it's unlikely.

If you check the voltage at the wire when not connected to the switch it should be +12V relative to earth (same conditions as above) if it is a filament, may not be if it is LED. If you don't measure any voltage there it could indicate a problem.

The Lg wire from the switch to instrument pack also goes off to the engine ECU, so some other effects may go on depending on the circuitry in the ECU. If the bike is in neutral you can't do any harm with testing this wire, it will either be isolated or grounded when connected, so either condition is safe.

5aa67cab830ab_neutralswitchNC.jpg.ee9ee0763fa32549f63842eeda59ab12.jpg

 

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twinpot

Thanks Embee we will take look a see what’s what.  I will post the results of the investigation.

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trisaki
4 hours ago, twinpot said:

Thanks Embee we will take look a see what’s what.  I will post the results of the investigation.

Definitely positively in neutral if like my guzzis  they lie  ! 

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embee

I'm not sure what the requirements of the manual NC are for starting, clutch in/out etc, but if the engine is running and the gearbox is definitely physically in neutral, when you put the sidestand down the engine should keep running, this will show that the ECU knows it is physically in neutral. If the engine stops when you put the sidestand down the ECU thinks it is in gear.

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Tex

On an automatic car you can’t select a gear from neutral (or park) unless you have your foot on the brake. The ECU measures the resistance of the stoplight bulbs. Same thing with a ‘twist and go’ scooter, if you’re not pulling a brake on the ECU won’t allow the starter to engage. Maybe the ECU reads the resistance across the neutral light? Or are they LED these days? 

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embee

The ECU wire connects to the Lg going directly to the neutral switch. I'm pretty sure it will use the connection going to ground when the switch closes as the determination of being in neutral. Switching to ground is a very common method for such inputs, it's relatively reliable.

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twinpot

Checked and wd40'd the speedo block connector connection which has not cured the problem.  My lazy brother owns the bike and and is doing the work.   He now says he cant be arsed with the effort and will do without the neutral light.  I will sort it with him next winter when the service work is carried out.  Thanks for the help and advice.

 

 

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machinman
1 hour ago, twinpot said:

next winter

🤤🤤

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