Vantage dead on start button press up, Engine fuse box?

[Mish 80]

Hello, another month, another problem...

Got in car. Put keys in ignition.
Detached trickle charger while fuel pumps charged. A warning about no rear lights(one wasn't connected while drying out).

Foot on clutch and also fully down on the accelerator.(Trying to build oil pressure after 6weeks no usage). Red light on start button pressed it...
Everything went black, no interior lights, no red alarm blinking light, no central locking, no electric window, no window drop, no boot release. No sure if there a click or anything mechanical as had my noise cancelling headphones on.


Battery is 12.7v. Fitted Oct 2024.
Disconnected battery and left off 10mins, reconnected and repeated a few times. No change.
Pressed the Battery disconnected yellow button behind the drivers seat(BDS).

No fuses blown in the boot, engine or passenger side box.

Voltage is showing on both sides of the BDS.

Connected the Ctek to the battery directly, no change.
Connected Ctek to the engine connection points and dome lights and red light returned. Put keys in dash and it was really faint but it said 'HW P/N:
4G431 0849CB'
Seats move and windows make twitching noises on their own. Hazard light switch results in no external blinkers but the button blinks and the dome lights dim in sequence.

13.3v charging on battery terminals with the engine Ctek mounted to the engine.
Both sides of the BDS have+ voltage with the battery attached. So it's not the BDS.

Boot fuse box is getting 14.1v when charger attached. 1.92v when no charger connected and no key.
No fuses seem to have voltage in the boot or engine bay.


Engine bay, all fuses are okay using a MM. No voltage on any when the ignition is off. Including the 60amp and the 40amp that sits separately nearby under its own cover.

I'm worried about low voltages effecting the other electronics so have not done much testing with the ignition key in.

At this stage I think it's the engine fuse box has completely failed when under heavy starting load. How do I test this theory? Under neath is there a good feed input to test that it's getting 12-14v.
I can't seem to see much info on the relays and what they do.

Ideas?

Edited by Mish 80 on Sunday 30th March 15:48

[LTP]

Try putting a decent-sized jump lead between one of the underbonnet body castings and somewhere on the engine block. Make sure you have good connections, then try again.

[Vsix and Vtec]

It could be the main fuse. They don't go very often, but when they do, it's the last place anyone looks.

[Mish 80]

Vsix and Vtec said:

It could be the main fuse. They don't go very often, but when they do, it's the last place anyone looks.

Where is this beast in the Vantage??

It's Ford transit part apparently.

Feels like a fuse as it was sudden at the point of high load, cranking the engine

[kabman]

That doesn't look like a fuse. The diagram on it suggests a flip-flop relay.

[Mish 80]

So I traced the live power from the battery under the carpet to a bolt roughly where your heels are in the drivers seat. It is getting 12v+. Smaller guage wire appears go to the boot fuse box, which has 12v.

I was looking for a relay or fuse or anything near the BDS, couldn't find anything. Rang a dealer, said my car, an early 2005 example might have some differences to 06+ cars but I should still have some basic electrics working. I did see a thread about a DBS with that 190amp fomoco relay, but can't see it in my car near the battery, could it be further into the engine bay?

Next I'll see if the live from the interior by the pedals, actually makes it further into the engine bay, see if I can find the exterior exit point of this behind the wheel arch.
A side from the battery jump point in the engine bay, where else should I find a permanent 12v?

Anything to check in the CEM cabin fuse box?