Under Hood 12v that is only on when car is on for transponder wiring

[MadBee93]

Can anyone tell me a good 12v source that is under the hood and only on when the key is in ignition and turned on? I don't mind splicing into a wire. I'm installing an AMB transponder (very low amp draw, approx. 0.1 amps). I thought I could just use "add a circuit" in the fuse box, but most of the fuses in there have 12v all the time. The only few that are switch with the car on are in places that made it impossible to fit the "add a circuit" unit.

thanks for any help!!

 

[2013DIBGT]

Post #5 here talks of an option

http://www.allfordmustangs.com/forums/2005-2010-mustang-talk/186153-need-switched-12-volt-source-under-hood.html#post1638810

 

[MadBee93]

thanks! I found the wire.

In case anyone find this thread doing a search, here is what I did:

You want to tap into the red wire with yellow stripe that goes into the connector right beside the ECM (NOT one of the connectors that go into the ECM). This wire is a 12v power source that is only on when the car is on. Picture below:

It helped a lot to disconcert the upper and lower ECM plugs so that you can pull the entire section of the wire harness up and out, to give you more room to work. See picture below:

This is what it looks like all back together and the AMB lap timing transponder wired up:

Use this line for low current applications only! If you need more than a few amps it would be best to use this line to trigger a relay connected directly 12v power at the battery or at the fuse box.

 

[lito]

That wire is power to the injectors and managed by fuel pump relay/fuse. That as the the red that is on the other extreme of the C110 (coil) are there for an unknown reason to me as they don't have a matching pin/wire on the other side of the C110 connector.