There are a couple of ways to do this 1) Take a wire direct from the positive terminal of the battery to the fag lighter - but you MUST have an appropriate thickness of wire and a fuse as near to the battery terminal as possible (just in case the next owner of the car uses the lighter for its intended use)
2) Find a spare fuse in the fuse box if there is one and tap in to there - again using the correct size of wire. The sat nav, you see, will only use a small current so a thin light duty wire will work fine. The ciggy lighter uses a high current which would burn out the thin wire though, and this could be a fire risk. So, if you go ahead, use substantial wire but add a fuse holder with a 3 amp fuse very close to the power supply and all will be safe. Make sure you observe the polarity too, to avoid sat nav damage. Have fun!
John, June 2008
