Electrical coil polarity

Discussion in 'Fox 5.0 Mustang Tech' started by madspeed, Mar 20, 2013.

  1. Mounted my coil under the fenderwell during a recent wire tuck and cant seem to find my pic showing which terminal is + and whichvis -. My aftermarket ignition has color coded leads, but oops. Which is which?
  2. They are normally marked + and - inside the terminal. You can hook it up either way but it will reverse the flow and you may see a decrease in performance . Here's how we used to check the polarity using a voltmeter years ago.

    Hook up a voltmeter with the neg lead to the plug terminal and the pos lead to a ground. Set the meter on the highest volt range. Crank the engine over (don't start it), and you should see an upward reading of the voltmeter(don't worry about the number). If the voltage goes down negative, your coil is hooked up wrong. To correct it reverse coil primary leads. Do not worry about the coil markings, but make note of them for future reference. It will also work with an old school voltmeter. The needle should swing UP and not down.
  3. with the coil facing toward you (post to the front plug in the back) positive is on the left.
  4. thx, ill have to pull mine out to look. its mounted way up under the fender
  5. Red/green wire is 12+ volts from the ignition switch
    Dark Green/yellow goes to the TFI module. This would normally be the place to pick up the Tach signal for an aftermarket tach.
  6. ive got an aftermarket ignition and no factory wiring intact. Just need to know which terminal on the coil is which

  7. In that case, your best bet is to contact the company that made the ignition system and ask them....
    Multispark ignition systems like MSD will seriously confuse a tach if it isn't connected to the proper place.
  8. no no no, i know which lead is which, I need to know what terminal on the coil is positive and what terminal on the coil is negative. Factory style coil