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f f i i n n d d i i n n g g t t h h e e 1 1 2 2 V V s s w w i i t t c c h h e e d d i i g g n n i i t t i i o o n n w w i i r r e e
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 lose power when the key is in the start position to make more current available to the starter motor.
H H o o w w t t o o f f i i n n d d ( ( + + ) ) 1 1 2 2 V V i i g g n n i i t t i i o o n n w w i i t t h h y y o o u u r r m m u u l l t t i i m m e e t t e e r r : :
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 excel-
lent 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 display 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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