wiring identity (1 Viewer)

[B-well]

lost indicators ,fuel gauge, panel lights, replaced 15amp fuse in number 1 as in manual, all okay on ignition except when ign/gen light goes out fuse blows. disconnected dash board checked printed circuit changed bulbs around just in case one was shorting, however same again. start engine oil light goes out, indicators work, fuel gauge working but as soon as i rev engine to extinguish ignition light, fuse blows. checked charge rate , alternator charging okay. checked relays and swapped like for like all okay. On back of fuse disconnected light blue wire with red tracer any ideas what this may feed as every thing appears working.
vehicle 1995 Hymer on Fiat cab.
can anybody give me a clue to where else to check out as i say all appears to work except when vehicle is charging. having difficulty locating wiring diagram for model

 

[aba]

sounds like it could be a split charge / fridge issue possibly after the relay.

is there anything else not working anywhere in the van ????? as this could be the source

 

[B-well]

no, all habitation area works, fridge charges while vehicle is moving on 12v, Heating fires up think this is related only to cab area. As stated fuel gauge goes off along with indicators and panel lights, replace fuse all okay again until van starts charging and ign light goes out.

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[hilldweller]

Let's be 100% clear....

Remove the blue wire.

New fuse.

Engine on and revving.

All OK, everything works.

Is that it ?

====================

I would take out my variable power supply, connect to blue wire, crank up the voltage measuring the current.

Or take a headlamp bulb ( 50W or 5A ish ) connect to battery, connect to blue wire, rev up. See what happens. At least no more than 5A will flow.

Or just tape up blue wire until the great day "THAT is what is is !".

It certainly looks like a relay clicks in at 14V or some gadget goes short circuit at 14V.

 

[B-well]

thanks for reply yes that's right something is shorting at 14v but cannot establish what, at this stage as indicators and fuel gauge along with panel lights are okay at 12v but will try current measure /headlight bulb test . thanks again

 

[FULL TIMER]

I'am no expert but if the fuse only blows when the alternator has a charge output it sounds like a fault within the alternator to me or possibly a voltage regulator,as far as I'am aware you shouldn't have to rev the engine for the red light to go out, well I don't in any of my vehicles.

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[B-well]

thanks full timer my thoughts as well however Alternator veleo was checked and found to be okay not sure though if regulator is independent somewhere on vehicle or built in as i took Alternator to auto electrician and he said Alternator was not the fault, after i described the problem but elected me to bring vehicle in next week if i still had problem as he could sort it.
so armed with that info i thought i would try to solve.
If i get time today will go and play with Hilldwellers idea to see what i get. mechanic lad said put nail across and see what burns.

 

[B-well]

the blue wire with red tracer obviously feeds panel and indicators and fuel gauge but disconnecting this from fuse box they do not work, will keep on trying to solve this.

 

[hilldweller]

the blue wire with red tracer obviously feeds panel and indicators and fuel gauge but disconnecting this from fuse box they do not work, will keep on trying to solve this.

Yesterday you said that when you disconnect the blue/red everything works normally.

I once went through this exercise with a machine in California, time problems did not help, got nowhere for ages, THEN I found out the guy I was helping was colour blind. Good game.

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[B-well]

must admit somewhat panic at trying all methods to solve issue especially hard when you think it should be simple to eliminate certain items.
for update ; found amp loss from blue wire was under 1 amps. checked all wiring, turned every unit on , lights,fan,radio, heater, emergency flashers ect to reduce habitation,. battery down to 11 volts. stuck in 20 Amp fuse by mistake every thing worked , replaced with 15 amp fuse as recommended all okay and working still,
so have by sticking in 20 amp fuse created something, of course could have disturbed wiring loom and solved problem. not sure whether to leave well alone or jiggle everything to see what happens,
I have handful of blown fuses if any body can find a use for them.

 

[FULL TIMER]

have a look at any wiring looms near the cab heater I seem to remember there being an issue with wires rubbing through near there. another thing is check the earth connections I assume your base vehicle is a ducato they normally have earthing points on the inner wings look like a round ring of male spade connectors sometimes these get a bit crabby and can cause problems especially with lights, it might be that you putting in a heavier fuse helped to create a better connection as it seems to be ok now

 

[B-well]

Full timer many thanks, did ensure all earth connections were cleaned but like the idea that heavier fuse may have created connection, suits me as everything seems okay at present, will await until i get me Dad up and will go under bonnet and try wiring loom in case this re creates initial problem and as i go through eliminating wires he can keep eye on fuse/gauge.

fingers crossed all is well
.

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