The male 120v electrical connector on the end of my block heater plug must have shorted out and melted internally, no biggie- 116,000 miles of getting pasted by road crap is is worn out. I got a new plug at the hardware store and I am having trouble finding what wires go to which part of the plug. There are 3 wires going into the plug and they are all black. Does anybody know the ground of the 3? I understand that as long as I have the ground connected right the other two don't matter which prong they go onto.

Thanks,
Douglas DC-9-32

 

2 wires should show continuity between them. The one that doesn't is the ground.

 

If it is the flat 3-wire cable, the wire in the middle is typically the ground. It should actually have the green insulation that may become visible when you pull the outer two wires apart to seperate them for installing the new plug.

 

I would be carefull. If the wire melted, it may be due to a bad plug heater. Entire trucks have been known to spontaniously combust as a result.

If you have a test lamp, put the clip on the positive of your battery. When you touch the ground wire, the light will come on.

As for the other two wires, for a heater they do not matter, but do not assume this for other electrical gear in the future.