Today was a big diagnostic day in the shop. The main issue? A John Deere 8320 that starts, runs for a few seconds, and dies — until it finally goes completely dead.
This wasn’t a battery issue. This was electronic: CAN power, grounds, relays, ECU failure, and everything in between.
Follow along as I test, trace, and finally track down the culprit.
Also included in this video:
• Diagnosing a 9620RX that won’t throttle up
• Full road test after verifying active codes
• Replacing the DEF dosing unit on the 9620RX
• Swapping and programming the ECU on the 8320
• Cold-weather gear-up segment before heading out
• And finishing the day with reviews of two Milwaukee M12 tools (extended-reach ratchet, Gen 2 Stubby Impact)
This video is loaded with real diagnostic steps, real failures, and real solutions.
Let’s get into it.
⏱️ CHAPTER MARKERS
00:00 – 8320 starts & dies
04:27 – Milwaukee M12 Soldering Iron / repairing wiring
09:57 – 8320 still won’t start!
11:35 – 9620RX will not throttle up – DIAG
14:00 – 9620RX ROAD TEST!
16:31 – Time to go out in the COLD! Gearing up
17:54 – Back to the 8320 – ECU replacement
20:25 – Programming ECU
21:46 – Time to FIRE it up!
25:00 – 9620RX replacing DEF dosing unit
33:13 – Milwaukee M12 extended-reach ratchet review
38:15 – Milwaukee M12 Gen 2 Stubby Impact review
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And as always — keep that green iron moving!
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