Tiny,
Welcome back..I think you are correct about the one wire coming out of the heater, but I think it is the only wire you can SEE!
I played with the heater motor out of my 55/1st (6v?) before I wrote the post above. It indeed has only one wire coming out of the heater area...the OTHER wire, the ground, is a little short dude that exits the motor the same as the power wire, but, goes to a screw attached to the heater (ground).
On my old truck heater, this is all hidden in back where you cannot see it when the unit is installed in the vehicle.
Your advice about the "never" word is well taken, I usually try not to say it, and might has stepped on my toes on this wire issue.
Stuart