Power wires on tomtom 520

[fcat]

Have just cut the end of my cigarette lighter lead so i can hard wire my 520 into my car, usually theres 2 wires, 12v and a ground, however theres THREE !! theres red/white and black

Anyone any ideas whats what ?

cheers

[IanS100]

I expect the Cig lighter end on the TomTom lead is a voltage reducer as the input voltage is 5v as far as I know. I wired an extra cig lighter in tandem with the original & have it hidden behind the dash - the power lead goes into this

[Andy_P]

STOP!

As Ian surmises, if you do this you will put 12 Volts up the TomTom which will blow it up immediately. The TomTom requires 5 Volts not 12.
I'll post this now and continue in a second reply.

[Andy_P]

Right, for info, the three wires you have got are;
1. positive volts,
2. negative volts, and
3. a "sense" wire that monitors the actual voltage at the TomTom end of the cable, so the correct 5 Volts required can be accurately delivered. If that cable breaks, the supply will actually increase the voltage (because it thinks it is too low) to a point that will destroy the TomTom itself. This was a common fault with one batch of very early supplies but is much less common now.


Getting back to your situation.....

What you NEED to do is keep the cigarette lighter adapter in the circuit as it reduces the raw 12 Volts down to the needed 5V.
If you can, you need to safely splice them back together as they were, or buy a new one...

What many people do is wire in a new cigarette lighter SOCKET behind the dash.

Maplins sell the required socket, part number FE42V.

or you can use an extension lead and cut the plug off THAT:

for example this one (part number BV47B):


or this one (part number A51HA):


Be aware that the fuse in these extension leads is in the PLUG, so if you cut that off (or use the FE42V socket with your own cable) you need to ensure you are suitably fused elsewhere. Either run the wiring to a spare fuse, use an "in-line" fuse holder, or put your new connector in parallel with the existing socket wiring).

You can then plug the original power supply into the new connector and hide it all away neatly.


If you aren't COMPLETELY confident about this, get qualified help.

An alternative, that doesn't involve any wiring expertise would be to use one of the commonly available cigarette socket doublers, such as this (Maplin part number L93AW):

and plug the extension cable above into that.

[fcat]

Thanks for all the inf, got a extension lead, chopped the end off and all is wired in and up and running!
cheers again

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