I have been in the process of putting heated mirrors from an expedition on my 97 F150. There all mounted ran the wires took power from my wire leading to my cig lighter to the switch and grounded each side on it's own. The mirrors I bought were used plugged them in passenger side works but no go on driver. Got money together and bought another used unit from ebay. Thought it worked buy then nothing. So got more money and got a new aftermarket one figuring all will be good acted like the used one thought it started to heat up but then nothing. What am I doing wrong something in my wiring. Ohm reading and 13.3 on new mirror looked around online and you want under 10 so think messed that one up as well. Any ideas please.