12 Volts switched from behind nav screen GS Mk 4

[Lexus4Me?]

Hi all,
I have had a good search involving mobile phone fitting on the GS (mine is a 2012 Mk 4 450h with Mark Levinson). I've decided I need a secure location for my mobile phone and want it charging on the go and to be visible so I can use it as a Sat Nav. I've narrowed my search for a holder down to a Voltbeam Sensor 2 which provides wireless charging and a clever automatic hold and release facility. I've no doubt that I can locate it suitably somewhere above the dashboard but, and here is the thing, I don't want a charging wire dangling across the car to the USB socket in the armrest. I can find a 12V to 5V regulator and I'm pretty sure I can lead a wire with a micro USB plug attached neatly out from around the screen to go to the holder.

I would really value advice on locating suitable switched 12V wires that I can tap into behind the nav screen or radio. I know that I can delve around with a voltmeter but one never really knows what one is connecting to and if doing so might have adverse affects elsewhere in the car.

Any advice greatly received.

[Herbie]

1 hour ago, Lexus4Me? said:

I know that I can delve around with a voltmeter

That's really the only way to do it

Quote

but one never really knows what one is connecting to and if doing so might have adverse affects elsewhere in the car.

There won't be any adverse effects on anything else. All you're doing is taking a supply, you're not feeding anything back in.

If you still prefer to err on the side of caution then you'll need the wiring diagrams to work back to the fuse and check on the rating, but I'd imagine that the regulator would draw such little extra current from the chosen circuit as to make no difference whatsoever.

[ColinBarber]

Before going to all that hassle, have you considered a flat cable that can be routed around the glovebox/centre console to the USB socket? I use this method which has the benefit of giving me connected audio rather than having to use Bluetooth.

 

[ColinBarber]

otherwise, spend €3 on an hour access to the wiring diagrams for your vehicle.

https://www.lexus-tech.eu

[Lexus4Me?]

Thanks for the advice fellow members. In the event I decided to follow instructions posted elsewhere and remove the trim around the infotainment screen, the trim around the radio/cd player, the cup holder/seat heater/vent controls and the gear shift plate and run the charging cable behind these back to the back of the "cigar lighter" socket from a small gap I filed out on the top right of the screen surround. Most of these were surprisingly easy to pop out (two hex headed screws on the gear shift plate) although the trim around the screen is held in at the top by three poppers with small weakly threaded screws retaining them. Unscrewing the screw didn't work - the screws just turned but didn't withdraw and just levering the poppers out was brutal and difficult. What one needs to do is to lever under the head of the popper and then use a short screwdriver to undo the screws. Both the poppers and the screws can just be pushed back in for refitting - on doesn't need a screwdriver.

Since the mobile phone would normally be connected to the "cigar lighter" outlet this seemed safest and is easier than trying to connect to a spare terminal on a fuse box. Slightly worrying however was just how thin the wires to the socket were (key fob for comparison) and I've put "cigar lighter" in inverted commas because I suspect trying to use the socket for lighting a cigar would at the least blow a fuse if it didn't melt the wiring! The socket is labelled 12 V 20 W and my phone charger is using most of that.

I'm pleased with the neatness of the arrangement - the short length of lead in the photo below is all that can be seen of the wiriing. Using an inductive charging phone holder means that the lead is connected to the holder not the mobile phone so it doesn't need connecting and disconnecting each time it is used. In the end I elected for a CHOETECH 15 W Wireless car phone holder/charger because it had a suitably higher power compared to the Voltbeam (7.5 W) which i initially considered. I like the way it automatically grips the phone when the latter is placed in the holder but wish I had bought a model which would release even when the supply was turned off. As it is I have to turn the car back on to to free the phone.

I'm just a bit disappointed by the bulk of the suction cup and hinged parts supporting the holder. The abundance of cheap fittings which are available with action cameras like the Hero Go Pro seem much better but are, as far as I can see anyway, incompatible with mobile phone holders.