I know you removed the DSP amp and replaced the radio but I didn't like to suggest it may be a self inflicted fault. You've just got to hope it's in the wiring along the sill shorting to ground and not have to admit you've spent 3 days looking for a problem of your own making. Although it would qualify for the My biggest cock up thread......

Ok, so I've unravelled the whole loom in the sill as far as the dashboard. No splice and no signs of a short. The loom continues up in to the dash past the kick panel connectors and short of removing the dash I can't follow it any further.

Does anyone know the route the purple wire takes from here? I think my best option is to figure out all the things it goes to and start testing the plugs for those to try and identify where the fault might lie. I might poke my nose in to the ETM again and see if I work it out. Hopefully it'll be easier now I've got a more concrete path to look at.

I don't mind it being a fault of my own making. It means it's less likely to be something serious like a completely dead BECM and something I'm able to fix myself :)

I've confirmed the short to ground with the multi-meter. With one prong on an earth point the purple wire gives 1ohm.

If I disconnect the plug from my radio it shows nothing.

Dead radio? Lovely Chinese electronics...

Sounds like the radio is toast. With that disconnected does the dash now power up and the fuse remain intact?

Yeah, I realised right after posting that I should do that next.

Dashboard comes right to life :)

Bloody Chinesium...

I suppose the question now is.......

Does the oil pressure light go out and stay out?

That's a question for tomorrow!

I bought an oil pressure gauge from eBay too. It arrived this morning which was a pleasant surprise - the estimated delivery date was Wednesday to Friday next week.

I'll hook that up and hopefully have a more immediate answer rather than waiting for it to reach operating temperature with potentially lower than ideal pressure.

Glad you found the problem! Somewhat surprised that a feed to what I'd consider an accessory/entertainment/non-critical bit of kit in the vehicle would cause instrumentation to fail, but its resolved at least.

And I suppose if the engine still started and ran, it wouldn't have caused a problem while driving if it happened beyond a loss of the dash...

It's the permanent live supply so ordinarily it would only draw a tiny amount of current to keep the stations stored. That would have been another clue if anyone had realised, he'd got an ignition switched supply so if the radio hadn't died it would have come on but with no stations stored.

So it's up and running again. Nanocom is working now too!

My passenger side window switches seem to be suffering. The front one will go down but not up. The rear one won't go down but makes a noise when I press it up.

My spare switchpack works perfectly but is much older and faded grey :(

Not important for now but I'll have to see about replacing the switches in the switchpack.

Black and purple as ground pass through that dreadful C0229 which you show as "little corroded". Make sure that is clean well! The ETM gives it for my MY (00) as ending in "RH rear of engine compartment near Engine Compartment Fuse Box"

Before you start go crazy, get the multimeter and check for continuity in the ground wires (both black and purple black) at the OBD plug and from C0229 (the purple/black one) and follow them to the grounds on the chassis.

Again, if you have positive 12V at the connector and doubt the ground, you can make a temp connection directly to the ground bolt in the A-pillar kick panel to get your nanocom started ...

The Nanocom is working :)

I do need to go back and clean that connector once the contact cleaner arrives though.

Glad it's sorted - and not in the BECM at all...

Just to clarify a couple of things though... on the ignition wires you mentioned there was no power on them - which isn't the test I do on them. I use the continuity test or even the low range Ohm setting on the multimeter to check for continuity to ground, rather than a voltage. A lot of the things on the P38 (which I think is what confuses a lot of garages) are controlled by a connection to ground to activate something - rather than getting 12V to something.

Switchpacks... the actual window switchpack component is screwed into the back of the trim and can be removed and swapped over. Also the switch caps themselves come off if that's what are faded (again with the whole switchpack unscrewed from the trim) .

If you don't want the old switchpack, then I might be interested in it to add to my collection of ones to repair.