That "Oh No What have I done" moment - completely dead after fiddling with the head unit [Resolved]

[grumpydad]

Hello,
I hope someone somewhere can help me! I am very new to car maintenance and it seems I have inadvertently killed my new car.

We bought a 2016 T6 Caravelle a month or so ago. It had had a few modifications done to it, including a remap, a suspension upgrade, and an Alpine ILX-F903D head unit replacement. These all had receipts for their fitting by businesses by its first owner.
All was working fine, but the dangling USB cable going into the dash niggled me somewhat, so I bought a USB3 face-fixed socket. I unscrewed the headunit screen, pulled out the trim, pulled out the unit out of the dash. It turns out the USB cable hanging out of the dash wasn't even plugged into the back of the headunit, it was just dangling back there.

I removed the USB cable, fitted the USB socket to the panel just above the lighter socket in the tray, plugged that back in to the back of the head unit. I almost stopped there but had a look around - there were unused sockets ("Aux Input" which I'll never use, and one for the wheel remote was empty so I looked around to make sure I hadn't accidentally unplugged it - there was no corresponding plug hanging around back there that I could find). I replaced the head unit, trim, etc, but the head unit didn't turn on when I turned the key in the ignition.

So I removed it all again, made sure all the plugs were firmly in place, replaced it all in the dash and now the van seems "dead" when I turn the key in the ignition. The dashboard (speedo, rev etc) doesn't light up or do its sweep, there is no turn-over when trying to start the engine. The van does lock with the remote key, though, and the ventilation fans come on.

I have to say I don't know where to start troubleshooting something like this - I had thought I would be up to a USB cable swap but it would seem I've exceeded my skillset in a catastrophic way. Can anyone help?

 

[CJW]

I’m no expert but, if it was me, the first thing I’d be doing was checking all the fuses.

Hi, the dash lights just stoped working and van starts but will not run, think its the fuse, but where is it please?

Maybe this thread is part of your issue? There are far more experienced people on this forum than me, though.

 

[grumpydad]

Thankyou very much CJW- I'm very new and still finding my way around, I'd done a search with very general terms but got overloaded with lots of results.

I've pulled out the bottle cooler and found the fuse box, I'll try replacing the dash fuse and report back.

If this has blown, would it stop the engine from turning over? There is no turning over at all.

 

[CJW]

I’d suggest changing the dash fuse - if that works (just for the dash), it might be indicative of multiple fuses blown. If it doesn’t work, then another line of enquiry is needed.

 

[Howzat]

I'm betting you've blown the BCM fuse. The fusebox under gearstick, 5th fuse down on the right hand side from memory.

 

[Magpie1832]

On the halo 9 there is a little screw holding a plastic plate on behind the screen. If you do t put this in then it will not power up. There is a micro switch under the screw.
Oops missed the rest that all is dead.
Check fuses first like the rest have said.

 

[grumpydad]

Thankyou for your suggestions!
I went back out to the van to try screwing the little trim plate back on - I had not secured the trim while I was testing it all - but no, still nothing on the dash. I can hear motors from the aircon/ventilation, and the hardwired dashcam powers on, but there is no ignition. The doors lock, and the (electric) side doors operate too.
I'll get some fuses from the shops tomorrow and try replacing the dash fuse and the BCU Starter feed as mentioned above (that is an astonishing memory you have there, Howzat!)

One other thing did occur to me - the Alpine Halo 9 has an additional box wired into the back of it to interface it with the CAN Bus, called the APF-X300VW. I found two wires coming out of it that look like a rubber boot may not be gripping properly/may have failed. There's some exposed metal on the black one. I'm a bit wary of plugging two wires of different colours into each other, but they would fit together. I'm going to see if I can find out what they do if I can find the installation instructions for the Halo9.

 

[JiMsHaDY69]

Thankyou for your suggestions!
I went back out to the van to try screwing the little trim plate back on - I had not secured the trim while I was testing it all - but no, still nothing on the dash. I can hear motors from the aircon/ventilation, and the hardwired dashcam powers on, but there is no ignition. The doors lock, and the (electric) side doors operate too.
I'll get some fuses from the shops tomorrow and try replacing the dash fuse and the BCU Starter feed as mentioned above (that is an astonishing memory you have there, Howzat!)

One other thing did occur to me - the Alpine Halo 9 has an additional box wired into the back of it to interface it with the CAN Bus, called the APF-X300VW. I found two wires coming out of it that look like a rubber boot may not be gripping properly/may have failed. There's some exposed metal on the black one. I'm a bit wary of plugging two wires of different colours into each other, but they would fit together. I'm going to see if I can find out what they do if I can find the installation instructions for the Halo9.

View attachment 153754

The black cable end is a bullet connector (I think that's the name of the connector type) and whilst it is designed to be fit into the type of connector on the end of the yellow wire I would 100% check the manual as it's generally same colour to same colour when making connections, although there are always exceptions.


Looks like the manual for this interface is available as a download from Alpine in the support section of this page:

Alpine - APF-X300VW CAN to UART interface for VW platforms (MIB-PQ - Seat, Skoda and VW)

Alpine - APF-X300VW CAN to UART interface for VW platforms (MIB-PQ - Seat, Skoda and VW)

www.alpine.co.uk

Good luck!

 

[CJW]

That cable appears to be labelled ‘BATT’ - battery?

 

[CJW]

…which could indicate that there’s a live end somewhere back there. Can you find the black, yellow and red bullet connectors? Are they all accounted for? They appear to spur from the same point on the module.

 

[JiMsHaDY69]

Looking at the manual there should be a yellow, red and black that are not connected to anything and they're for an external DVD or tv tuner. If you don't have either of these installed them don't worry about those cables. Check all your fuses first, blowing a major one such as the BCM could cause everything to be dead as you describe, but I'm no expert.

 

[CJW]

@JiMsHaDY69 is right - that’s the onward power to the DVD, which explains why the boot is on the module end.

 

[grumpydad]

Thankyou for all this -I've got the installation instructions from that link above and will trace it all out to make sure there's not a cable out of sight somewhere.

I'm taking a break for the night and will let you know how I get on tomorrow!

Cheers all, I'm very grateful!

 

[grumpydad]

So... no fuses blown.
No local autoelectrical people can see us for a couple of weeks. I called the RAC, chap did what he could, including running multimeter over the fuses, etc and it looks like both the headunit and the dash/immobiliser are off. He noted that the "Infotainment" fuse was missing from the fusebox (looking at the chart downloaded from here) but clearly it was working fine before I pulled the headunit out, and I actually haven't touched that fuse, so must be an effect of the Alpine unit install (or a T6 model variation?)

Anyway, he advised recovery to a main dealer, so I'm in the middle of arranging that.

I am obviously worried about the end cost of all this, but I've learned an awful lot already. It just would have been a shame to have been annoyed by that USB cable..!!

 

[CJW]

Keep us posted... fingers crossed it's a simple and cheap fix.

 

[Deaky]

Did you remove any fuses? Can you send a pic of your fuse box. It's very likely that you could have a fuse in the wrong hole

 

[Loz]

It might be one of the main supply fuses in the e-box under the starter battery.

 

[grumpydad]

Cheers for any help. So far we're drawing a blank on any help for the next 4-6WEEKS!

I've attached a pic - the top of the picture shows what I think is a "hardwired" dashcam that came with the van.

 

[Deaky]

Are you absolutely sure all the fuses are good. Have you removed them and checked them out of the fuse box?

Did you remove any fuses when you were working on the head unit?

If you did then it is possible you've pushed it back in the wrong place. Look closely at each empty fuse slot. If you can see a metal terminal in both sides, then there should be a fuse in there.

On a side note, the piggyback fuse holder that's been added is upside down. The wire should be exiting the LHS for both circuits to be fused correctly.

 

[oldiebut goodie]

Looks OK to me! Which is the true UP?