With a multimeter. The easy way is to unscrew, disconnect and remove the sending unit from the tank for testing. Once removed, connect the multimeter to the chassis of the sending unit and the isolated stud that was wired to the fuel a gauge. Depending on where the sending unit's arm is positioned different resistance values will result.
high voltage sending unit that sits atop each sparkplug
No.
The easiest way would be to purchase the special socket that fits that sending unit to remove and install.
The sender is in the tank and something is wrong with it. It probably needs a new sending unit.
Back of the block, next to the distributor.
Yes it has an oil pressure sending unit next to the distributor.
The oil sending unit is located slightly lower than the distributor on the engine block.
It's to the right of the distributor.
It is on the back of the engine, next to the distributor.
chrysler/dodge/plymouth dealer
It is on the back of the engine, next to the distributor.
It is in the fuel tank.
It is on the back of the engine, next to the distributor.
Something this old the sending unit has failed.
It is the two wire sensor next to the thermostat housing.
It is on the front of the engine, just above the oil filter.