I suction cup my I3 to the plastic gauge cluster, in between the speedo and temp sensor. Works perfect, stealthy, and I can remove whenever. The cord reaches the power outlet, but my next project is to add another outlet somewhere under the dash.

 

Thanks for the advice, your right the cable is long enough to reach but I've decided that a better location is in the bottom right of the window (RHD car) so the cable has even less distance to travel

I'm looking for an extension lead to save hacking apart the adapter. I assume theres a hole somewhere leading though to the engine bay and fusebox and then it's just a matter of a but of contortionism to get the leads to meet up under the dash. I guess a lot of cable ties will prevent it coming loose or rattling.

In order to crimp the wire do I just need a 'crimper'? I assume I don't need a soldering iron. Sorry for the dumb questions. I'm not totally stupid but I've not done anything like this before and would rather ensure I have all the stuff I need in one visit to the hardware store

 

In US cars, that connector that xviper's post shows is under the dash all the way on the left side, right next to a convenient grounding bolt (the bolt is easy to spot because it already has a bunch of wires on it).

As xviper showed, the connector has one always-hot, one ignition-hot, and one lights-on-hot that accept 1/8" (I think) spades. You don't have to go through the firewall. Go to Radio Shack and get a 12-volt receptical and wire it in to one of these (I'd pick the ignition-hot one). HPH

 

My advice is that for any adapter that might have electronics inside the cigarette adapter regulating voltage, it's BEST not to take it apart!

Just get a female cigarette lighter and cut off the end and tap that into your standard 12v+ ignition / ground and then plug your lighter in under the dash. Then run the wiring up the pillar.

I have a pic of the plug that we used for my m3 since we had to relocate the cigarette plug after I put my push button switch there. (it's dangling right under the shiny silver remote) for my cell, etc.



Any electronic issues, give us a ring since I work on european cars all day long

rick