Changing head unit accessory power slightly

[JOZ]

Hey i want to do a slight rewiring so that i connect the accessory power for the head unit in parallel with the power for the interior light and the power it normaly gets when the key is turned
so that my head unit therefore stero would be on whenever either the key is turned or the interior light is on so that i can get out of the car and grab stuff out of the boot or something and listen to music then i can lock the car and then the light turns on and stero aswell and same for when im going to the car when i unlock it the stero will turn on
Im just wondering if this is possible and if it is how hard it would be to do, and also if anyone knows about doing the same thing for a VS as my mate has a VS and wants to do the same

Thanks

[vn_v6]

so you can crank it in the car park and show your fully ick subwoofer bro, and yeah you can, exactly how you said......

[JOZ]

well i dont have a sound system its just stock but replaced the head unit... and where abouts would the wiring be thats easiest to add the wiring in? is it close to the fuze box? because i was also hoping to use one of the spare fuze slots and run it through a fuze just so i can pull the fuze out so then its just like i hadnt done anything... and do you know any good reliable websites with wiring diagrams and maps?

[axemurderer101]

it is possible just depends on what size fuse the interior light uses and how much power the cd player draws, you would need to use a diode so that when you have your key on it doesnt back feed and keep your interior light on. but if the fuse size is too small you could just use a relay.

Edit, just remembered if your vx is like the vs the power wire for the interior light is constant and the light is switching by the earth which is most likely done by the bcm.

[tk55]

it is possible just depends on what size fuse the interior light uses and how much power the cd player draws, you would need to use a diode so that when you have your key on it doesnt back feed and keep your interior light on. but if the fuse size is too small you could just use a relay.

Edit, just remembered if your vx is like the vs the power wire for the interior light is constant and the light is switching by the earth which is most likely done by the bcm.

axemurderer101, is the interior light switched via a relay? if it is, then probably best to use a spare relay slot and using the same turn on signal to trigger the added relay. so whenever the lights come on, so does the head unit . just parallel the 12v from this relay contact to the head unit's original 12v power input so that it gets power either when lights come on or the key is turn on.

and as soon as you pull the added relay out, everything is back to normal like nothings been done

[axemurderer101]

im pretty sure it is switched by the bcm, i guess you could run some 3mm twin from under the steering wheel to the 2 wires going to the light which you could use to switch a relay and then run a constant power to the relay and then run your power out from the relay to the headunit