Is it a fuse somewhere?

[JAL]

I own a Fiat Ducato 2008 Motorhome. I let the battery run down so got my jump pack, connected it under the bonnet, jumped in the cab, switched on the ignition, all lights came on properly so I turned the key to start it.  There was a click and everything went dark.  I can see that the jump pack is connected but the vehicle is not connecting to it any longer.  There is no flow of electricity going from the jump pack.  I’m guessing I must have blown a fuse but which one and where is it?

your help will be greatly appreciated.  Thank you.

Jeff.

[TeamRienza]

Can’t help with the potential cause or fuse location, but consensus is that jump starting a Motorhome can cause damage to the habitation control box and electrics.

The habitation side of the van needs to be isolated before jumping the starter battery. I am sure experts in Motorhome electrics will give better advice than I can offer.

good luck.

Davy

[Labby]

There are fuses at the positive terminal of the starter battery but  a jump start would not normally cause these to blow , it could be worth checking that the connections that you have already made to the under bonnet jump start points are good and that your jump pack is charged up ok.

If this does not work you could  try connecting the jump pack direct to the starter battery which is under the passenger side floor of the cab , beneath a removable cover.

[Alanb]

I agree with Labby.  Check connections, and that your jump start pack is charged.

Are both the battery, and engine block earth straps in good condition?

Attached is a jpg version of the Fiat eLearn diagram E5010 applicable to x250 starting and charging.  If you are happy with diagrams OK, otherwise we should  be able to guide you through the necessary parts, should the need arise.

Alan

Edited December 2, 2023 by Alanb

[JAL]

My jump pack is fully charged and the connections I made were good.  If I connect the jump pack directly to the battery I can get ignition lights.  If I connect under bonnet I get nothing.  As mentioned before the first time I connected under bonnet I had ignition lights until I turned the key to start then engine so it can only be a fuse between the under bonnet positive connector and the battery but which one is it?

I cannot follow the wiring diagram to save my life sorry!

[onecal]

Hi 

Check your earths (- ground wires) and any wiring for damage to the fuse box and in the engine bay  . 

Regards 

Edited December 3, 2023 by onecal

[Labby]

The power supply to the starter motor  from the battery is through  the 500amp maxi fuse which is the large fuse on the positive battery terminal connection plate having the main large positive starter cable  attached to it , the connections there on each side of the fuse may need to be checked , Along with the actual battery positive terminal post connection.

Edited December 3, 2023 by Labby

[Ninian]

Hi,   If you have a meter you should be able to check continuity across the fuses on the + battery terminal.

[onecal]

Hi

Hopefully he will pick this up on checking his wiring loom in the engine bay and all connections to the fuse box Also as in the diagram supplied by Alanb there is a junction fuse box J002 that needs to be checked carefully at the rear for damage as do B009, B001,H001as Labby states for good connections on both sides of all fuses Again you say you have connections off your battery but nothing within your engine bay Why not replace with a new battery and connections and start from there ? Please do not start at any wiring if you are not competent, get a professional to check it out for you The wiring schematic Alanb has provided is easy to follow and if you are having difficulty following as you say , this is why I recommend you have it checked professionally especially  as you are unable to see a blown fuse or damaged or corroded wiring (or loose connections)

Regards

[Alanb]

1 hour ago, onecal said:

Hi

Hopefully he will pick this up on checking his wiring loom in the engine bay and all connections to the fuse box Also as in the diagram supplied by Alanb there is a junction fuse box J002 that needs to be checked carefully at the rear for damage as do B009, B001,H001as Labby states for good connections on both sides of all fuses Again you say you have connections off your battery but nothing within your engine bay Why not replace with a new battery and connections and start from there ? Please do not start at any wiring if you are not competent, get a professional to check it out for you The wiring schematic Alanb has provided is easy to follow and if you are having difficulty following as you say , this is why I recommend you have it checked professionally especially  as you are unable to see a blown fuse or damaged or corroded wiring (or loose connections)

Regards

The statement above "Also as in the diagram supplied by Alanb there is a junction fuse box J002" is incorrect.  The prefix "J" is used on eLearn wiring diagrams to denote a separately mounted relay.  There is a box denoted B002 on the diagram. This is the cab fusebox on an x250, and plays no part in the engine starter motor operation.

I do agree with the need to check the earths, both the main battery earth C003 at top LHS of the diagram (located in battery box), and the particularly since in view of the age of the vehicle, the engine block earth strap. @euroserv, who was a fleet owner, has previously suggest changing these straps every four years. I have to rely on the diagram, but this strap between engine block / gearbox assembly is represented by C002 to C003 on the diagram, again top left.  It carries starting and charging currents.

1 hour ago, Labby said:

The power supply to the starter motor  from the battery is through  the 500amp maxi fuse which is the large fuse on the positive battery terminal connection plate having the main large positive starter cable  attached to it , the connections there on each side of the fuse may need to be checked , Along with the actual battery positive terminal post connection.

To be correct and avoid confusion the 500A fuse protection the starter motor is a "CAL" fuse which can carry large currents for normal cranking time. A Maxi fuse is a large blade fuse as may be found in the engine bay fusebox, B001.

Alan

[onecal]

Hi

My apologies as to my incorrect reference to Junction fuse box J002, yes it should be as per diagram B002 and failure of connections  here on the fuse box affects the instrument panel E050 as the OP originally states (everything went dark) This needs to be checked very carefully throughout as do all earths and the wiring loom itself Again I have no idea how competent the OP is so I recommend he has it looked at professionally if he is unable to find a blown fuse , loose electrical connections  or damaged wiring which may cause a lot of damage to other electrical instruments on board . 

Edited December 3, 2023 by onecal