Radio On/Off (ignition lead)

[Omni]

Hey, tried to search to see if anyone else has asked this before but didnt find anything. I cant remember if the stock radio stayed on when the keys were out like the power windows do but I know on most new cars this is the case, until you open the doors that is. Well the other day I decided that I'd try a diffent fuse to hook my ignition wire up at to see if I could get it to stay on until I opened my doors, but it seems that non of the fuses in the car are actually hot when the keys are out. So my question is has anyone done this and if so are their any fuses inside the car I can hook up to or do I have to run a wire through my firewall to the other fuse box? I'd rather not tap into a wire inside the car unless I have to, but thats always an option. Thanks.

[Deftech]

well, the windows fuse should stay hot for 43 seconds or until you open a door. .But that is about all you will get. Unless you want to use the fuse for your dome light. High prob. you will kill your battery one day though.

[J3adSeed]

i wouldn't tap into anything. there's not much you can tap into and it seems like too much current to screw with it to me. i'm assuming you have a aftermarket head unit since you're wiring stuff right? well its real easy, if you want it on all the time (why i don't know), just connect the acc power to the constant power and connect them both to constant. see you have one wire that gives the head unit power all the time, for the clock and stuff. see what size fuse that wire is. then you have the wire that works when the car is on. see what size fuse that is. if the constant wire is a bigger fuse than the switched fuse, i'd connect them both to constant. but if the constant is smaller, then its probably only there to keep settings, while the power is being pulled by the switched power. in that case you should run a separate wire. it wouldn't be hard to run a separate wire though. 10-12 gauge depending on what kinda head unit you have. if you have 50 watts x 4, they already have a pretty big power wire and thats for 2 feet (probably 14 gauge or so) in which cause i'd use a 10 gauge. make sure you fuse it at the battery so if it ever shorts to the metal of the car (either wearing at the grommet, car accident tearing it, etc.) you won't fry the head unit and the battery and start a fire.

[Omni]

Hmm almost forgot about this thread... but no I dont want the head unit on all the time.. all I need it to find a fuse that stays hot until the door is opened when the key is out of the ignition.. there is an LED in the window switches that stays on and that would probably be a perfect wire to tap into, but I have a feeling that only comes on at night.. but I havnt really payed attention to it during the day.

[J3adSeed]

that'd probably come on at night, but there's probably a wire that tells it when to turn on or off regardless. like there will be power and ground, a wire to tell it the lights are on and to light up, and a wire to tell it if the key is in. so one should work, you would have to use a relay though.

the one problem you may see with something like a door switch is that the radio turns off whenever the door is opened. you can rig up an elaborate relay system that will turn the radio off if both the key is out of the ignition and a door is opened. that could be done. well i figured a way to do it w/ 3 relays but the problem is as soon as the door is closed it would turn the radio back on. so that won't work.

the door switch goes ground when the door is opened. it stops when the door is shut. if you can find a wire that goes neg from the time the door is opened until the car is back on then i could do it. here's the 3 relay setup i came up with you just need to replace that door - with one that won't go back when the door is shut. there is one i just don't know where.

3 spdt relays

relay 1:
30: 12v
85: ground
86: ignition
87: empty
87a: to relay 2

relay2:
30: 12v
85: from relay 1
86: door - (this needs to be - once door is opened and stay until that way
87: to relay 3
87a: empty

relay 3:
30: 12v
85: ground
86: from relay 2
87: empty
87a: to head unit ignition lead

that's probably no help since i don't know the wire you need. i'll think about it.