Here is the wiring diagram for the Model 27L (Cars built from 1919 - 1921
thru S/N 2-2100-7):
For cars built from 1921 and after with S/N 2-2101-7 and up, Milburn
opted to change back to a simpler, 9-pole controller (vs the 12-pole
contactor used with the 1919-1920 Model 27L above).
We have no wiring diagrams from literature at this time for this later
controller. However, the Milburn Parts List does show the plan
diagram for the controller. And from this diagram, we can deduce
the wiring diagram: