I want to transfer my TomTom Sat Nav into my Octavia from an Audi A4 where I had permanently wired in a power supply feed. I previously used a fused cigar holder that ensures that the Tom Tom device is supplied with the correct voltage. The TomTom plug that fits into the cigar holder transforms the voltage downwards.

Can anyone advice where I can pick up easily a live feed under the dash to connect in the cigar holder.

I don't think my first post made clear what I am trying to do. I have a "loose" cigar lighter assembly that I wire under the dash via an in-line-fuse power feed.Once in position I can plug my Tom Tom plug into this lighter socket permanently under the dash and overcome the problem of trailing wires in the cabin. This is the approach that Halfords take when installing SatNav. I need to know where I can conveniently pick up a power feed under the dash. Any ideas?

According to Haynes, the existing cigar lighter is fed from fuse 41 (15A fuse) by a red and black wire and a brown return wire going to an earth point next to the steering column.

What I would do is find these two wires by tracing them back from the cigar socket on the tunnel and use 3M connectors (as used for add-on caravan wiring) to tap off for the additional cigar socket. You could, of course, use any any convenient earth return point.

Make sure that your new wires are at least as big as the existing wires. Contrary to popular belief, fuses are there to protect the wiring as much as the sub-circuit. Using say 2 Amp wires with a 15 A supply fuse will cause a fire if there is short in your sub-circuit. (I know there is a fuse in the cigar plug but the fault could be in the socket).

Mike

p.s. I assume yours is a Mk1 Octavia

Edited 17 June, 200917 yr by pikpilot
Clarification

Thanks for this.

Any idea how to expose these two wires as simply as possible?

as pikpilot said, i used the cigarette lighter and took a feed off that (took out the central console to get to this) to run power up the central tunnel (above the carpet) up to a four way adaptor hidden inside the dash to provide wiring to my sat nav and detector when required.

Either that or you could take a feed off the fuse box......i was not that brave!

To expose depends on your experience and confidence i guess......you can strip it with a tool, or a stanley knife carefully cutting around the wire in 2 places then peeling it away and tapping into it if that makes sense, or do what i did, just cut it and reconnect with suitable device once new wires are in place (ie 3m or block connector)

I remembered what the connectors are called that I have used before in similar situations. They are 3M Scotchlok and available from a number of sources - try caravan spares places first. They are often used to connect the tow-bar wiring to the car lights wiring.

See:

Scotchlok Connector: 3M UK & Ireland

Watch the demo video for a "Run Tap" about one minute into the demo.

Using these connectors you don't need to cut or expose the conductor as they are insulation displacement connector (IDC).

Mike

Make sure that your new wires are at least as big as the existing wires. Contrary to popular belief, fuses are there to protect the wiring as much as the sub-circuit. Using say 2 Amp wires with a 15 A supply fuse will cause a fire if there is short in your sub-circuit. (I know there is a fuse in the cigar plug but the fault could be in the socket).

OR ,if you do use lower rated wiring ,fit an inline fuse immediatly after the tap -might not be a bad idea anyway ,as shouldn't imagine a sat nav will draw much current .( or skip this idea totally and fit a lower value fuse in the fusebox, if you plan only to use the sat nav on that circuit)

I took my feed off the radio supply as it was close, never had any problems in the 4.5 years I ran it for.