Finding The 12V Switched Ignition Wire - Directed Electronics AM1 Installation Manual

I I M M P P O O R R T T A A N N T T ! ! Do not remove the fuse holder on the red (H1/11) wire. It ensures that
the control module has it's own fuse, of the proper value, regardless of how many
accessories are added to the main power feed.

finding the 12V switched ignition wire

The ignition wire is powered when the key is in the run or start position. This is
because the ignition wire powers the ignition system (spark plugs, coil) as well as the
fuel delivery system (fuel pump, fuel injection computer). Accessory wires, on the other
hand, lose power when the key is in the start position to make more current available
to the starter motor. Use the following procedure to find (+)12V with your multimeter.
1. Set to DCV or DC voltage (12V or 20V is fine).
2. Attach the (-) probe of the meter to chassis ground.
3. Probe the wire you suspect of being the ignition wire.
The steering column harness or ignition switch harness is
an excellent place to find this wire.
4. Turn the ignition key switch to the run position. If your
meter reads (+)12V, go to the next step. If it doesn't, probe
another wire.
5. Now turn the key to the start position. The meter dis-
play should stay steady, not dropping by more than a few
tenths of a volt. If it drops close to or all the way to zero,
go back to step 3. If it stays steady at (+)12V, you have
found an ignition wire.
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