Driving along at 40mph when i flashed the lights at someone i knew, then the engine cut out, no lights on instrument cluster, speedo stuck at 40mph, rev counter stuck at 3,000 , fuel gauge stuck at half way and temp gauge the same, turning ignition off and on makes no difference, the engine will turn over when key turned to start position but does start. all the electrics inside are dead, have checked all relays and fuses both inside and engine compartment.

pulled the supply cable of the fuse box and there is 12.5volts, plug it back into fuse box and volts drop to 2.9volts????? put a 12volt feed to the fuse box connection and instrument cluster reset the dials all to zero and dispalyed mileage clock etc for approx 10 seconds

has anyone come across this before or have an idea why the voltage drops down when plugged into the fuse box?

thanks for any help or suggestions

Pull all the relays and fuese out of the fusebox.
Refit one at a time and see which one causes the volt drop.

My guess is something, probably a relay has failed inside, but possibly wrong side of a fuse, so no fuse popped.

There'll be a main relay and an ignition relay, but I'm currently 120 miles away from my Haynes's.

portland_bill said:

Pull all the relays and fuese out of the fusebox.
Refit one at a time and see which one causes the volt drop.

My guess is something, probably a relay has failed inside, but possibly wrong side of a fuse, so no fuse popped.

There'll be a main relay and an ignition relay, but I'm currently 120 miles away from my Haynes's.

Click to expand...

Did try that, did it with all the fuses and relays in both the interior fuse box and the engine bay fuse box , none of them put the voltage back up??? but if i put 12 volts straight to the interior fuse box the dash lights up, hazard light swith works then, i suspected the headlight flasher switch as it cut out just after flashing the headlights, thanks for your help

ok done a few more checks today, if i remove the power supply to the fuse box inside the van there is 12.5 volts, plug it into the fuse box and relay T09 under the bonnet clicks and voltage goes down to 2,9 volts, remove the power supply to fuse box and only goes back upto 7.8 volts, if i remove the T09 relay it goes back upto to 12.5 volts.

I then connected an electrical pump to the power supply, the relay clicks and voltage drops right down to 0 and the pump doesnt run, disconnect the pump and voltage goes back upto 7.8 volts, will only go back to 12.5 when the T09 relay is removed, so the power supply at the fuse box is not right, as soon as a load is put on it the voltage drops to 0

what could cause this, should i just rewire a 12v feed to the fuse box??? would it need to be fused if i did this??? it is not the fusebox that causes the voltage to drop as it does this as soon as any load is put on it when it is disconnected from the fuse box, i tried swapping the T09 relay for another relay but made no difference

So what does T09 relay power?
From your description it seems that may be faulty, unless it is supposed to do this.

Try a jump lead from engine block to clean point on body.
Or battery negative to body.
Check battery terminals.

manxevo said:

ok done a few more checks today, if i remove the power supply to the fuse box inside the van there is 12.5 volts, plug it into the fuse box and relay T09 under the bonnet clicks and voltage goes down to 2,9 volts, remove the power supply to fuse box and only goes back upto 7.8 volts, if i remove the T09 relay it goes back upto to 12.5 volts.
i tried swapping the T09 relay for another relay but made no difference

Click to expand...

may be of some help..

https://www.fiatforum.com/ducato/448863-06-fiat-ducato-immobilizer-lock-out.html