Wiring Harness - John Deere LA120 - LawnMowerForum I need some detailed pictures or schematic of the wiring harness for a John Deere LA120 riding tractor. Any help would be greatly appreciated. 1. Where does the black wire for highlights go. (Probably ground?) 2. Where does the two pinned red wire go? (is the fuse missing?) 3. Where does the White wire go? 3137531374 John Deere Wiring - YouTube Click to view on Bing4:09I made sure that every wire was clean making a good connection at the connector. Every place there was a ground wire it was taken off and cleaned and replaced.Author: Om FishingViews: 15K Need wiring schematic for john deere L120 lawn tractor Does anyone have a wiring diagram for a John Deere 100 series lawn tractor. mercurymike: I need a wiring schematic for John Deere LA120 lawn tractor. If you would e-mail one I would greatly appreciate it. The engine runs but when I engage the mower nothing happens. John Deere LA120 100 Series Lawn Tractor Parts - Quick John Deere LA120 100 Series Lawn Tractor Parts 42 Mower Deck Quick Reference Guide. Click the part number below to view and order John Deere LA120 100 Series Lawn Tractor Parts 42 Mower Deck, or search illustrated diagrams to determine the part you need.