This thread is ancient but still very helpful. I just installed one of these and wanted to provide some part numbers and links to make it easier for the next person.

Being new to this it took awhile and an email to Ed at Great Plains to figure out what I needed. For a lot of people here this is just basic stuff.

Great Plains

CS156-15-LR Quantity 1
Connector, 0.156" Plug, 15 Pin

08-52-0113 Quantity 2 (Order a bunch more than 2 in case you mess up crimping or want to shorten wiring to make the install cleaner)
Crimp Contact, 0.156", Trifurcon, 18-20AWG

John’s Jukes (The only supplier I could find)

HI-08CS Quantity 1
https://www.flippers.com/catalog/product_info.php/coin-token-comparator-p-3187

IWISS Weather Pack Terminal Crimping Tool - Wire Crimper for Delphi Metri-Pack 150, 280 & Weather-Pack Terminals 0.35-2.0mm2 AWG22-14 https://www.amazon.com/dp/B0732W6HQR/ref=cm_sw_r_cp_api_i_paQECbH7F6AN3

I hope this helps someone.