Easiest place to hook into switched 12V

[SeaMist]

Hi guys,
I am trying to install a thumper portable battery. It has a control box which I believe is an isolator and the instructions say to connect 'this little black wire' to something coming off the ignition. They suggest the wiper motor loom.
Anyway they obviously dont expect the battery to be under the drivers seat where I have installed the isolator control box. I was hoping to take 'the little black wire' across to under the driver's seat and pick up a keyed 12 v point there but my research seems to indicate that there is only permanent live 12v available there.
To the question: Where is the easiest, closest ignition switched point to the battery box where you can gain enough access to attach this wire. :eek:

Please?
Gwen

[Blknight.aus]

if its TDI, I tap the fuel cut off solenoid in the engine bay and then oil pressure switch, with no oil pressure and the ignition on the relay shunts no power with oil pressure (and therefore engine running) the relay connects power. From memory the easiest place to tap ignition switched power is the back of the fuse board for the brake lights/wiper motor or the hot side of the brake light switch. It does depend on how much current you want to draw.

[SeaMist]

It's a 2011 90. I don't think current is a major issue, I think it's a control wire.
Thanks.
Gwen

[Blknight.aus]

ahh so you have the ford defender....

havent tried to tap onto them yet Be carefull where you grab it may bear on the operation of the ABS/TC if you grab the brake switch.

IMHO the safest option is to grab a VSR (voltage sensing relay) hook that up to the back of the ciggy lighter and use the output of the VSR to supply power to the signal wire.

[SeaMist]

Thankyou, I think that's the best idea. Certainly easier than any of mine :D

[Beckford]

ahh so you have the ford defender....

havent tried to tap onto them yet Be carefull where you grab it may bear on the operation of the ABS/TC if you grab the brake switch.

IMHO the safest option is to grab a VSR (voltage sensing relay) hook that up to the back of the ciggy lighter and use the output of the VSR to supply power to the signal wire.

How big a relay would you use?

Thanks.

[Blknight.aus]

depends on how much power you need.

the VSR's that I use can drive about an amp If I need more than that I use the VSR to drive a bigger relay.

[SeaMist]

Thanks for your help guys, Job done.
For anyone's reference:
Access to the back of the ciggy lighter is easy by undoing the two screws in the centre dash console and (at the risk of ripping off all your nails) pulling the whole assembly forward from near the top. If you undo the 'fuse box looking thing' that is not a fuse box on the passenger side you can gain enough access to feed wires up to the centre console.
Connect and you're away :-)
Gwen

[Blknight.aus]

just remember the ciggy lighter comes on with AUX (if the radios on then the lighters on) you may find yourself inadvertently draining your battery if you leave the radio on.