# Chausson Flash 08 Ducato 130 Multijet



## Des2

Hello, Can anyone help. The fuse blows everytime I engage reverse. Where is the reversing switch? How do I acess it? Any other tips. Thanks Des


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## rayc

Des2 said:


> Hello, Can anyone help. The fuse blows everytime I engage reverse. Where is the reversing switch? How do I acess it? Any other tips. Thanks Des


The reversing switch is on the top of the gear box to the left of the air filter. It is not the easiest to get at to remove the connector. It would be worth knowing what else you have connected to the circuit e.g. reversing camera. Have you checked that the bulb blows if the reversing lamo bulb is removed?


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## Codfinger

*fuse*

I dont think the switch will be the problem as I expect it just switches to earth, I expect the problem is elsewhere as Ray sugest's your reversing camera , check your light cluster too to see if water has got in somewhere, try changing the reverse light bulb too 
Chris


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## Des2

*Reversing fuse*

Thanks for that.
No problem at light end only happens when reverse gear is engaged.
One thing I noticed building up to the error was that the light flashed as 
I put it into gear but when in gear the light was out again it then started fusing. Tomorrow I will check the circuit. If the switch just goes to earth there must be a permanent live to the cluster, which will be easy to check.


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## rayc

*Re: Reversing fuse*



Des2 said:


> Thanks for that.
> No problem at light end only happens when reverse gear is engaged.


I am trying to understand your statement. If there was a short in the bulb holder, wiring or the bulb itself then the only time the fuse would blow is when the operating voltage was connected via the reversing lamp switch.

Incedentally I believe that the switch voltage is +ve because I have Hella rear light clusters fitted and the earth conection is common to all of the lamps in the cluster.


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## Des2

*I agree*

Chris suggested the switch was to earth but it cant be because as you say the earth at the cluster is common. I think I will find that somehow the cable has become dislodged and frayed to earth causing a fuse. I wll let the world know tomorrow I hope!


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## Des2

*REVERSING SWITCH UPDATE*

So I cut the cables they are very easy to get at. No short at switch!

When I put mulitimeter set on circuit test with noise! The noise is a regular intermittenet sound. Anyone know what that means normally, the complete circuit sound is constant.

My thinking is that the live side miust be ok because it would fuse on turning on ignition not just reverse!

So the short must be somewhere in earth side.

Any thoughts anyone!


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## rayc

*Re: REVERSING SWITCH UPDATE*



Des2 said:


> My thinking is that the live side miust be ok because it would fuse on turning on ignition not just reverse!
> 
> So the short must be somewhere in earth side.
> 
> Any thoughts anyone!


My thought are that you do not fully understand the workings of the circuit. If there were a short on the lamp or holder or wiring then the fuse would not blow until the circuit is completed i.e when the reversing light switch activated.

In other words if the bulb had a complete short in it across the element then this would have no effect untill the positive voltage was applied via the switch. Without the switch operated the positive supply does not get to the bulb and thus the fuse will not blow.

If you have a multimeter put it on resistance and remove the bulb.
Measure the resistance across the bulb holder contacts with the ignition switched off and the gear box in neutral. What resistance do you read?
Put the gear box in reverse, still with ignition off, and measure again. What do you read?


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## Des2

*Rubbish*

Fault must be in the live suppy going to the cluster


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## Des2

*Sorry did not see your reply!*

YOURS:My thought are that you do not fully understand the workings of the circuit. If there were a short on the lamp or holder or wiring then the fuse would not blow until the circuit is completed i.e when the reversing light switch activated.

Fuse does not blow till reverse is engaged.

To make myself clearer "the fault must be in the supply coming from the switch to the cluster, in the cable"


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## rayc

*Re: Sorry did not see your reply!*



Des2 said:


> Fuse does not blow till reverse is engaged.
> 
> To make myself clearer "the fault must be in the supply coming from the switch to the cluster, in the cable"


The fault could be anywhere in the supply after the switch, right up to the bulb itself and including the bulb. What you know at the moment is that when the live is switched through the reversing lamp switch that the fuse blows. Anywhere in the line from the switch, including any accessories such as reversing camera etc if fitted, is suspect.
Can you carry out the resistance checks refered to in my earlier post?

You said "When I put mulitimeter set on circuit test with noise! The noise is a regular intermittenet sound. Anyone know what that means normally, the complete circuit sound is constant".

I am not sure where you have your multimeter connected but perhaps it means that the sound does not indicate a direct short [continuity] but a higher resistance.

If you want to discuss further then please send me a PM.


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## Des2

Measure the resistance across the bulb holder contacts with the ignition switched off and the gear box in neutral. What resistance do you read?

With multimeter at 20m reading .01

Put the gear box in reverse, still with ignition off, and measure again. What do you read? 9.81

With multimeter at 200m reading (Remember switch is isolated)


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