I pulled my coil to test it today. My Haynes manual has a section for testing any coil older than 2000, but the coil they describe isn't anything like mine. I kind of guessed which wire was which, I think the connection that goes to the green wire on the harness is the 12v positive side. Anyway, with my guessing testing, it looks like the coil is bad. Can anyone describe to me how to properly test this 99 coil?

 

Another clue is the previous owner ran a hot wire to the coil when he was troubleshooting and left it hooked up overnight, killing the battery. I wonder if that took it out.

 

Quick way is to have someone crank the motor and have the coil wire slightly away from metal and watch for spark.Dont hold it without insulated handles on your pliers or whatever your using it might hurt .

 

It WILL hurt (if its a good coil). A shock off a coil can kill you.

 

Only accurate way is to get a good manual and test for BOTH primary and secondary resistances with a meter.

http://www.pacificcoastmanuals.com/F..._cherokee.html