Not really porsche specific but how would you go about figuring out which wire on the coil is the positive and which side is negative? I know the porsche coils are labeled but this is for a jeep. I tried putting a meter on the lines and taking a reading as I cranked which theoretically should give me a positive or negative reading which would make the choice easy but I just got positive readings no matter which way I put them on. Thanks in advance.

 

Disconnect both wires, turn th ekey to RUN and check for a voltage signal in reference to ground. I believe one wire should have 12V on it, this would be the "+" wire. The other wire should not have a voltage signal to ground. Also, the "-" wire usually runs to the "switch" - points, Hall sensor, or DME system, depending on vehicle.

 

Damn I knew I was forgetting something, "Turn the key to RUN", thanks Uranium 235.