A month ago I noticed ammeter not showing charge when running the tractor. Tractor has started for the past month and been used a couple days a week to mow for 2 hours or more each day. Battery was new in March and has never needed charging. I have been through John T's steps for checking the system. Ammeter jumps up to 20 when field post is grounded to body. Replaced voltage regulator with new (twice). Cleaned and checked all connections and continuity of wires. Replaced ammeter. Checked and double-checked wiring diagram in manual. With the cover off, I don't see any activity of the VR or cut-out switches when the tractor is running. Have polarized the VR multiple times. Any ideas or suggestions?