External Voltage Regulator for John Deere 10, 20, and 30 Series Tractors SKU: QT59178

When your tractor's charging system starts acting up—dimming lights, dead batteries, or overcharged electrical components—a faulty voltage regulator is often the culprit. This external voltage regulator controls the charging output from your alternator, preventing both undercharged batteries that leave you stranded and overcharged systems that damage expensive electrical components.

Why This Component Matters

• Maintains steady voltage output to protect your ignition system and keep lights bright during long work days
• Works specifically with 120-amp and 90-amp alternator systems on John Deere 10s, 20s, and 30s series tractors
• Weather-resistant housing built for outdoor agricultural use with secure electrical connections
• Controls charging output to prevent both dead batteries and overcharged electrical damage

Always disconnect the battery before installation and verify your tractor uses a 12-volt negative ground system. S&H Parts has been keeping John Deere tractors running strong since 1969—call if you need help confirming the right regulator for your specific alternator setup.