Good place to take a ignition live feed from behind dash?

[Siftah]

I've had a quick search but couldn't find anything relevant in the How-To section;

I'm looking to find a power feed which is only live when the ignition is on, ie: position 1 or above. I'm intending on using this to power a phone charger which is permanently mounted on the dash. Currently it's plugged into the cigarette lighter socket but it's a bit messy with the cable trailing.

I've got a cigarette lighter socket and cable ready and the intention is to stow it behind the dash with just the cable visible. I'd sort of intended on using scotch-locks (snap lock connectors) to tap into some existing wires - yes, I know it's a bit dirty but it's better than cutting and soldering into the wiring I think. Open to suggestions though...

Can anyone recommend a good pair of wires to use?

I suspect lighting will cause the LCU to give me problems so I'm thinking the radio head units power feed is probably best?

Total draw from the charger is around 500mA, so it shouldn't need to be too beefy a cable.

Ta in advance!

 

[Tweed]

Wahey, you're giving it a go then? Awesomes

got my charger ready to do mine, but think I want to take the power from the lighter socket so no help to you

 

[TH3R4POR]

I took a feed from the electric mirror fuse (using a piggyback double fuse with output) but I think there are actually empty fuse slots in the board you could use.

Just grab a multimeter and test.

 

[aquazi]

I hardwired my road angle and used the purple white wire from the vanity light next to the interior mirror.

Another other option maybe from the seat heater feed; which i belive the live was green and orange/ red.
I initially tried tried the ciggy socket but the live never cuts off on that - so i risked draining my battery.

 

[Siftah]

Wahey, you're giving it a go then? Awesomes
got my charger ready to do mine, but think I want to take the power from the lighter socket so no help to you

Yup, I'd been waiting to get some cleaning compound for the soldering iron but gave up in the end and sandpapered it, sort of worked so I knocked up the cable. Thought I'd best make an effort to tidy the car up for next weekend too!

I don't like the way the cigarette lighter socket is continually powered on as it means the GPS/Bluetooth in the TomTom mount will be constantly on broadcasting a signal and draining battery, so I thought I'd use something that goes off with the ignition

The prob with the bluetooth in it being on is that I suspect car thieves could confuse the bluetooth signal for there being a mobile phone in the car and the chances of my roof being slashed go up sharply :\

I think if I can find a good spot I'll also power the ElmCan wireless off it instead of the (constantly on) OBD ports power feed, for much the same reasons!

 

[Siftah]

I took a feed from the electric mirror fuse (using a piggyback double fuse with output) but I think there are actually empty fuse slots in the board you could use.

Just grab a multimeter and test.

Ah! I didn't even think of the fusebox... yeah, I know, pretty stupid in retrospect I shall do that and see, there must be electronic gadgets I don't have on the car or could pinch a few mA from. I guess the heated mirrors draw current from the mirror fuse too so that should be rated for a startup load of a few amps - sounds like a good bet!

 

[Siftah]

Another other option maybe from the seat heater feed; which i belive the live was green and orange/ red.
I initially tried tried the ciggy socket but the live never cuts off on that - so i risked draining my battery.

Where's the heated seat feed routed? Is that accessible behind the dash itself?

(Thanks for the suggestions so far everyone!)

 

[TH3R4POR]

If you use a piggyback fuse then you don't need to worry about the draw from the mirrors, the output is fused separately so you can use whatever rating you see fit.

Something like this will cure what ails you.

It's far easier/safer/tidier to use the fuse board than start splicing into heated seat loom etc, not to mention more reversible.

 

[Siftah]

If you use a piggyback fuse then you don't need to worry about the draw from the mirrors, the output is fused separately so you can use whatever rating you see fit.
Something like this will cure what ails you.
It's far easier/safer/tidier to use the fuse board than start splicing into heated seat feeds etc.

Oh! I'd never seen those before - I like that idea, much cleaner as you say, will try and get hold of some of those locally so I can get on with it, wicked, cheers

 

[TH3R4POR]

No problem, good luck!

You'll probably have to give the piggyback fuse holder a shave with a knife or razor blade to remove a little of the moulding on the sides as they are a tight fit, but it's nothing structural.

 

[AlanJ]

Used the 'lighter' live feed to hardwire my satnav mount in. Plenty of room and easy to lead the wire from the lighter socket and into the dash area.

 

[TH3R4POR]

Used the 'lighter' live feed to hardwire my satnav mount in. Plenty of room and easy to lead the wire from the lighter socket and into the dash area.

Trouble is the lighter is always on, so that won't suit everyone's needs.

 

[EdButler]

You should just go for the switched radio feed in my opinion. Pin 7 (the corner opposite to the locking clip on the connector)

http://www.isham-research.co.uk/quattro/wiring/Typ85/isopin.html
http://en.wikipedia.org/wiki/ISO_10487

 

[Siftah]

Been having a crack at this tonight but haven't made much progress - I seemed to be getting an earth from the feed I've wired into the fuse box (with a piggy back fuse-blade holder).

Measuring from the live from the fuse box to the earth on the cigarette socket I was getting nothing.

Measuring from the cigarette lighter *live* terminal to the feed from the fuse box I was getting -12v.

Didn't seem to get a good connection with the scotch locks either, but that's to be expected, they're crap - I'll bite the bullet and solder the connection in instead.

Not sure what I was doing wrong but I gave it up as a bad job.

On the plus side I'd re-soldered up the AUX-In cable and that now works a treat - the tantalum caps have definitely worked better than the polybox ones did.

Some days you're the fly. Some days you're the windscreen, tonight I was the fly.