Radio On Until Door Opened

ok so i want to add this feture to my truck but i have a question before i start i can see y this will turn off my radio but will it not turn back on when my door is then closed? or does my car know better or the radio just wondering i know this is proly a stupid question but any help would be great

Radio On Until Door Opened (Retained Accessory Power)

If you wish to keep the radio (or any other device that is powered by an accessory circuit) on until a door is opened, you can do so by creating a latch when the accessory is turned on with the relay shown below on the left, then breaking ground to the latch when a door is opened as shown with the relay below on the right. While this will keep the radio on, the entire accessory circuit will see 12V+ until a door is opened with the key in the off position.

itbeanew1 wrote:

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I am new to working with relays and this board. I would like to add this to my 2004 Mazda6 and have a few questions..

1. is it the same procedure for every car?

2. the relays shown in the diagram already in the car or      do i need to purchase these? if they are already in the car, which ones are they?

3. if i do have to install the relays, how do i go about doing that? do i have to buy a mini fuse block or what?

4. what does the black line in the diagram represent?

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1) pretty much, but it depends on if the door trigger is normaly float, +, or -. in any case the right hand relay can be wired slightly diffrently to have it work.

2) not in the car (otherwise it would work already). you may or may not be able to re-use one of the relays, but it is simpler to just add both so that you dont have to figure out stock wireing.

3) the relays come with mounting holes for screws, but most people just let them dangle or zip tie them to a wireing harnass. for the actual connections, automotive relays have quick-connect tabs so that you can crimp female quick connecters right to the wires and have them plug in to the relay directly. it is easyest if you use splice in connectors and scraps of wire to go to the relays.

4) the ground wire. this is usaly any black wire - if you are taping power off the radio harness there will be a ground there for you. the metal frame in the car is grounded too, so worst case you wrap a wire around a screw.

yamathegreat wrote:

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would i just change wire 87a on the right relay to 87?

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yes - this is because the relay (with your setup) is normaly closed, and opens when the door does. therefore the latch must de-latch on door open.

Hi All,

Serious newbie here looking to install the same relay set up.  I've read through all the tutorials & posts I can find on this and have a couple of questions:

1. For the 12V+ & ground, can I splice these into the respective wires already there for the radio?  Or should I run new leads from the fuse box & chassis?

2. I assume the fuse installed on the 12V+ lead should be rated a bit less than the amperage of the relay being used.  Is this correct?

Any assistance greatly appreciated.

Thanks Auex.

One more question (possibly a really dumb one but again - serious newbie here)... Am I reading the diagram correctly in that there is no connection between the car's and the radio's accessory wire?  So the radio's accessory wire goes into the car's radio harness and ends there?

Thanks again.

al3372 wrote:

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So the radio's accessory wire goes into the car's radio harness and ends there?

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Sorry - that last line should have read "So the CAR's accessory wire goes into the car's radio harness and ends there?"

12vbattery wrote:

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the car's acc must be somewhere

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