Boot accessory socket - not working, can't find fuse! Family holiday depends on it!

[mrh]

Hi,

The 12v accessory socket in my 2003 Superb has lost all power, the problem is that the towbar electrics (flasher unit) is powered via the cable that supplies this socket.

I assumed that one of the fuses in the fuse board would have blown. I looked in the manual, and tried Google, but could not determine which fuse it would be, so I then checked EVERY fuse in the board. But they are all ok.

Does anyone else have any idea where the fuse for this socket could be, or any other reason why there is 0v being supplied.

We're meant to be going away this week, in the caravan, but without this supply, I don't have any indicators on the caravan - so can't drive it.

Can anyone help?

Many thanks

Matthew

[VRSPhil]

The fuse is on the relay board under the dash, above the pedals. It's a stupid place for it.

I think you have to remove the lower dash trim to get to it. I think it also supplies the socket near the rear seats.

[mrh]

The fuse is on the relay board under the dash, above the pedals. It's a stupid place for it.

I think you have to remove the lower dash trim to get to it. I think it also supplies the socket near the rear seats.

Cheers Phil,

Hopefully it doesn't supply the rear seat sockets, as that one still works!

I'll see if I can find the relay board after dinner.

Many thanks - much appreciated.

[VRSPhil]

I'm probably wrong to be honest! I'm sure it will be the fuse at fault.

Good luck

[rwbaldwin]

The fuse is on the relay board under the dash, above the pedals. It's a stupid place for it.

I think you have to remove the lower dash trim to get to it.  I think it also supplies the socket near the rear seats.

+1

The fuse is on the edge of the relay plate so it's easy to miss. It's a 20A fuse.

[mrh]

Thanks everyone - finally managed to remove the lower dashboard to expose the relay board.

The board has 2 fuses - one on the left of the relay plate, and one on the right. They are both ok! So I'm no wiser as to why there is no power in the boot!

Any other suggestions?

Thanks again,

Matthew

[rwbaldwin]

Was it a factory fit towbar?

If so double check fuse 35 in the fusebox.

[mrh]

Update!!

Found a third fuse on that board! A white "25A" fuse, which has blown..... In the process of putting the fuse at the top of the board (yellow - 20A) back in, I managed to drop it down the back. My fingers are too chunky!

Does anyone have any idea what the 25A fuse may supply - apart from the boot accessory socket?

rwbaldwin - it was supplied on the vehicle when I bought it from the Skoda dealer, but I think it's an aftermarket retrofit. No fuse in 35.

Thanks to everyone for there very prompt help - we may yet be going on holiday!

Thanks

Matthew

[rwbaldwin]

The fuse you are looking for is between relays 53 and 100 on the edge. The fuse only supplies the luggage compartment accessory socket as it leaves the factory. If it had a 25A fuse in it, that's what I would fit - it may be necessary if you have a fridge

[mrh]

The fuse you are looking for is between relays 53 and 100 on the edge. The fuse only supplies the luggage compartment accessory socket as it leaves the factory. If it had a 25A fuse in it, that's what I would fit - it may be necessary if you have a fridge

Cheers for that. Off to fetch some fuses from a mate, will fit them first thing and see if we have success!

Many thanks!

[mrh]

Thanks to everyone's joint efforts, I now have power in the boot!!!!

The bad news is that it hasn't fixed the problem with the towbar lights...... but I'm now fairly confident that it is the flasher relay. Have tried a couple of caravan dealers and car spares places this afternoon, but without any success. Will have to delay the start of the holiday and head to a towbar fitter tomorrow.

In other bad news... one of the fuses I've taken out the check, seems to have triggered an "Airbag Fault" warning on the dash.

Does this sound possible? Or is it likely I have suddenly developed a real Airbag fault?

This trip seems to be doomed.....

Many thanks

Matthew

[rwbaldwin]

Check for loose wires at the towbar socket. Maybe this is what caused the fuse to blow in the first place.

RE: Airbag fault - If you removed its fuse, then you probably did cause the problem. You can only reset the fault with a diagnostic tool such as VCDS.

[mrh]

Check for loose wires at the towbar socket. Maybe this is what caused the fuse to blow in the first place.

RE: Airbag fault - If you removed its fuse, then you probably did cause the problem. You can only reset the fault with a diagnostic tool such as VCDS.

Thanks RW,

I've checked the wiring inch-by-inch from the socket to the relay box and it all looks ok. When I took the relay box out it had the tell-tale smell of blown electronics!

I have a 3rd party vag-com lead somewhere around (not sure I'll be able to find the drivers though). Off to hunt them out. At least I now feel confident that the airbag fault has been generated by me, not a real fault!

Thanks

Matthew

[rwbaldwin]

Yes - you can reset the airbag with VCDS-Lite and and a generic lead. It doesn't need to be registered.

When you have your lead installed, download VCDS-Lite from the ross-tech website.

[mrh]

Cheers - error code cleared, dashboard back to normal.

I think this is the faulty item..

Hopefully I can source an equivalent tomorrow.

Cheers to all for their help,

Matthew

[rwbaldwin]

Cheers - error code cleared, dashboard back to normal.

I think this is the faulty item..

Hopefully I can source an equivalent tomorrow.

Cheers to all for their help,

Matthew

That's the bypass relay. You are unlikely to find one that is a plug-in replacement, but 7-way versions are common these days. Make sure it's suitable for non-CANBUS cars.

[mrh]

Interesting - I'd convinced myself that it wasn't a bypass relay, as it only seems to control the indicators (the side lights etc operate fine with it unplugged).

Most of the bypass relays seem to have connections for all the lighting functions.

This unit has incoming connections for power (0v and 12v) and both indicators (L&R). The outputs are to the vehicle indicators and and the trailerboard indicators.

If I can find a standard unit I'll happily sort out all the connections to make them fit the current wiring.

Thanks again,

Matthew

Edited 9 April, 2012 by mrh

[rwbaldwin]

The indicators and stop lights are 21W each so are bypassed, to protect the flasher unit/brake light switch. Ideally, you would bypass the fog, reverse and tail lights too.