Are you sure?My van does not have the electric heat.
I have a 2015 250 and it has it.
See page 89 of your owners manual. Half way down the page under "Temperature Control" the last sentence says "Turn the temperature control knob to maximum heat to turn the auxiliary heater on". Suspect the fan must also be running.
No comment from Ford that some models do not have this feature.
The heater only works when the engine water is cold and the temperature knob is turned fully clockwise. It shuts off when the engine water reaches some set temperature. Do not know the temperature it turns off on the Transit.
My sold 08 Sprinter had the same feature. I had a Scan Gage on the Sprinter that displayed both water temperature and voltage. The voltage would jump from 13.5 volts to 14 volts when the heater turned off when the water temperature reached 145 degrees (if I remember temp. correctly). Very obvious when it turned off.
Sprinter required the Scan Gage because the 5 speed transmission would not downshift when it should. One other display was "load" which indicated the % load on the engine. It would peg at 99% and not down shift. If you manually downshifted the "load" would drop and fuel rate used would decrease. I do not miss that horrible transmission and enjoy the Transit 6 speed. Do not miss the Sprinter either.