The Ford Barn

Brian SATX · 06-05-2024, 07:09 AM

OK, I have one of those coil polarity testers sold by the vendors. The kind you use for a quick check to see if your wires are connected to the coil properly. It has been accurate every time I use it. Tried it on a friends car yesterday and it showed the wires were wrong on the coil(red light) We checked the coil visually and the wires were correct. Had to think why. His car has been changed to 12V Negative ground. Would that affect the reading? Is that tool set so that polarity of the car makes a difference?

As a side note, we were checking to see why he had an intermittent miss, usually in 3rd gear. We tried taking a nut off the + side of the coil and the post turned, not the nut. He got a new coil and problem solved.

06-05-2024, 07:09 AM	#1
Brian SATX Senior Member Join Date: May 2010 Location: San Antonio, TX Posts: 876	Polarity tester OK, I have one of those coil polarity testers sold by the vendors. The kind you use for a quick check to see if your wires are connected to the coil properly. It has been accurate every time I use it. Tried it on a friends car yesterday and it showed the wires were wrong on the coil(red light) We checked the coil visually and the wires were correct. Had to think why. His car has been changed to 12V Negative ground. Would that affect the reading? Is that tool set so that polarity of the car makes a difference? As a side note, we were checking to see why he had an intermittent miss, usually in 3rd gear. We tried taking a nut off the + side of the coil and the post turned, not the nut. He got a new coil and problem solved. __________________ Brian SATX