Technical Relay T10 (fuel pump) not engaging, 4-5A power draw from battery with key out

[pwhooftman]

On my X250 (2007 onwards) , 4-5 Ampere is drawn from the battery with the key out and all lights out. If i pull fuse F18 in the engine bay (powering the Ecu) the current draw stops.
Also, the only way to start is to hot wire pins 30 & 87 at relay T10, powering the fuel pump directly. So relay T10 doesnt seem to get 12V at pin 86 when starting. Altough this works, its not ideal (the engine keeps running if i pull the key for instance).

Any pointers as to look were for the current drawn & T10 not engaging?

 

[corcai]

You can get the full wiring diagram on the elearn cd in the downloads section. In general I'd check for water ingress in fusebox and ecu connectors and damage to the loom behind the headlight.

 

[CDK]

With the ignition key on, the relay is activated a few seconds to provide fuel pressure. After successful starting the relay is permanently powered.
I'm afraid you have an expensive ECU issue!

 

[corcai]

Was trying to post this earlier but couldn't on the phone. Water ingress is common in the fuse box corrosion can both break and bridge circuits, its possible to open it to inspect:
https://www.fiatforum.com/ducato/226940-07-ducato-160-multijet-wont-start.html?p=2408630

 

[pwhooftman]

Thanks all, will tackle the fuse box coming friday

 

[pwhooftman]

Took apart the fusebox this evening, already a tell tale sign at the black plug.

There was still a bit of moisture inside between the layers, cleaned it all up, sanded the contacts and put it back together. Will see tomorrow how it turns out.

 

[corcai]

Good job. If theres a wurth near you their kontack ol is good for cleaning and protecting.

When you get it working again your next job is to keep as much of the water out of the engine compartment as you can. Look at the posts on sealing the windscreen scuttle and adding better drainage.

 

[pwhooftman]

Tested this evening. Current draw at rest is down to 2,5 amps. I doubt if that has anything to do with the fuse box, i will have to investigate further by pulling fusses one by one and narrowing down the cause.

T010 is being fed 12volt when the ignition is turned on, turns out i forgot to reconnect the inertia switch in the passenger footwell, providing earth to the T010 relay :bang: . But, with the inertia switch connected, it engages as soon as i turn on the ignition (FPSon shows on the dials, indicators blinking & doors unlocking). I can disengage the inertia switch only with the ignition off. I truly believe the inertia switch is purely mechanical, so im stumped why it engages when ignition is turned on. I am contemplating bypassing it (engine starts & stops correctly that way), but i'd rather find out the cause.

 

[pwhooftman]

Turns out the AC clutch enages even without the ignition on & motor running. It even engages if i remove the fuses powering the AC compressor
I have just disconnected it for now, current draw in rest is down to approx 0.05 amps.

 

[corcai]

Turns out the AC clutch enages even without the ignition on & motor running. It even engages if i remove the fuses powering the AC compressor
I have just disconnected it for now, current draw in rest is down to approx 0.05 amps.

Relay contacts could be welded together.