AUTO OCCASION Voltage Regulator D663 for Delco 10DN/20DN 12V Negative-Ground — Direct-Fit Replacement

AUTO OCCASION voltage regulator D663 is a new 12V replacement unit designed to match Delco 10DN/20DN solid-state negative-ground charging systems for Buick, Cadillac, Chevrolet, GMC, Oldsmobile and Pontiac vehicles.

This compact, direct-fit regulator provides a straightforward replacement for worn or damaged factory regulators on compatible classic and modern GM electrical systems. Manufactured to meet key electrical and mechanical dimensions, the part is intended for 12V negative-ground Delco alternator assemblies and ships new from the factory in China. Before purchase, verify year, make and model compatibility and visually compare the part to your original regulator to ensure correct fitment.

Which vehicles and alternator types will this regulator fit?

The D663 regulator is built for Delco solid-state regulator platforms, commonly referenced as 10DN and 20DN series. It fits a range of GM-built cars and trucks that use these regulator types with a 12V negative-ground electrical system. Always check the original part number and connector style on your vehicle before installing.

• Compatible with Delco 10DN and 20DN solid-state regulator housings
• Typical applications: Buick, Cadillac, Chevrolet, GMC, Oldsmobile, Pontiac
• Designed for 12V negative-ground electrical systems
• Part number reference: D663 — compare to original for visual match

How do I confirm this regulator matches my original part?

Confirming fit is a two-step process: check the listed fitment (years, makes, models) and visually compare the new regulator to your existing unit. Look at the mounting hole spacing, connector type and the regulator's shape to ensure a direct replacement. If any detail differs, the part may not install correctly.

• Verify vehicle year, make and model against seller fitment notes
• Compare mounting holes, connector pins and physical dimensions
• Match the original part number or consult a parts diagram when in doubt

What should I expect during installation and performance?

Installation follows the same steps as the original regulator—remove the old unit, install the new regulator in the alternator or voltage regulator housing, and reconnect electrical terminals. Once installed, the regulator controls alternator output to maintain system voltage under normal electrical load. Use basic hand tools and follow vehicle-specific service instructions to avoid damaging connectors or the alternator.

• Simple swap-in for visually matching regulators
• Re-establishes voltage regulation for 12V negative-ground systems
• Follow vehicle service manual torque and wiring procedures

What are the product specifications and origin?

The regulator is sold new under the AUTO OCCASION brand with part number D663 and is manufactured in China. It is specified for 12V electrical systems and built as a solid-state replacement component. The listing emphasizes compatibility confirmation to prevent mis-purchases.

• Product type: Voltage regulator, solid-state
• Voltage rating: 12V, negative ground
• Condition: New — Part number D663
• Country of origin: CN (China)

Who is this for? This regulator is aimed at DIY mechanics, restoration specialists and professional technicians working on GM vehicles that originally used Delco 10DN/20DN solid-state regulators. If you need a dependable, direct-fit replacement for a 12V negative-ground alternator regulator and your original part matches D663 or the Delco 10DN/20DN footprint, this AUTO OCCASION unit is a practical option. If you are unsure, gather the old regulator's part number and photos, or consult a knowledgeable parts supplier to confirm fitment before ordering.