Radio on till door open

I suppose this is the circuit you used...

In this circuit, the radio will turn on whenever accessory power is restored to the radio (i.e., key is in accessory or run).

Note that the "Radio's Accessory Wire" signal is spliced into the existing power feed to the radio.  All this circuit does is tie constant +12 volts into the accessory power feed (via left relay contacts 30 and 87).  When you turn the key to off (and kill the accessory power), all accessories remain powered via the fused +12 volt source.  

To answer your question:  Power to turn on the coil of the left relay is provided by accessory power to the radio (to coil terminal #86).  The other side of the left relay coil (terminal #85) is grounded through the normally-closed contacts of the right relay (terminals 87a and 30).

Can you use this system to keep the ignition power running therefore the engine keeps running till the door is opened without the key in??

auex wrote: Can't link to diagrams on your hard drive.

This is a pretty cool feature I have seen on some newer vehicles. Can I add it to any of my vehicles? If so, some clarifications would be good....

• Radio Accessories Wire: is the power feed to the radio good enough, or must it be the Accessories wire in the ignition harness?
• Fused 12V+: Is this just any 12V power source. In other words, can I install a new power source? What size fuse shoud this be?
• (-) Door Trigger: I assume this is the door switch in the jamb of the driver's door (that turns the interior lights on)?

My appologies if these are silly questions, I just want to do it right.

Thanks.

Zilverado,

Power feed to the radio is fine.

Fused 12V+ can be any constant 12V source thats not controlled by the igniion switch. Use a fuse of the same size as installed in the fuse panel for the radio circuit.

Verify that your door trigger is (-), if so, just tap into it at the most convenient place in relation to where you place the relays.

Thanks Hpotup32.

I'll definitely keep this post for reference when I get around to doing this.

Z

You should put a diode behind where you tie into the radio power (i.e. between the fuse block and the splice) 

This will prevent the other accessories from getting power, which is a good thing for two reasons:  1) You will not overload the wire/fuse by backfeeding power to ALL of the accessories through it; and 2) you will not be draining your battery down by running your A/C fan.