Which side of the coil is negative?

Joined
Aug 28, 2005
Messages
14
I am installing a tach in a 1982 FJ40. I need to tap the negative side of the coil, but there are no markings on the coil and the wires are both same color (all original wiring and coil, I think). The wires all seem to go to the igniter on top. Both post on the coil complete a circuit to ground on the chassis with no power on at the switch. How else might I see which is negative?

signal-2021-09-09-185639_001.jpeg
 
Joined
Nov 25, 2014
Messages
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Location
Western victoria Australia
If the 12v marking is near a terminal. that will be positive. With the ignition on you should only get a voltage reading from one terminal. That will be positive. If you are getting a reading from both terminals you may have to disconnect both wires and test them both with the ignition on. You can use a test light if no multimetre.
 
Joined
Aug 28, 2005
Messages
14
If the 12v marking is near a terminal. that will be positive. With the ignition on you should only get a voltage reading from one terminal. That will be positive. If you are getting a reading from both terminals you may have to disconnect both wires and test them both with the ignition on. You can use a test light if no multimetre.
You are correct! Thanks... I did have to disconnect the wires...
 

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