Standard Ignition DS-647 Headlight Switch

Headlight Switch for GM Trucks and SUVs

The Standard Ignition DS-647 headlight switch is built for direct replacement in select Chevrolet and GMC applications. It uses copper alloy conductors for strong electrical transfer and is 100% tested for mechanical and electrical switching performance.

Compatible With 1990-1994 Chevrolet C1500, C2500, C3500, K1500, K2500, and K3500, plus 1992-1994 Chevrolet Blazer, C1500 Suburban, C2500 Suburban, K1500 Suburban, K2500 Suburban, and GMC C1500, C2500, C3500, K1500, K2500, K3500, and Yukon. The DS-647 also matches 1990-1991 GMC C1500, C2500, C3500, K1500, K2500, and K3500 applications.

• Direct, snap-fit attachment method for OE-style replacement
• 12-volt headlight switch design
• 6 blade terminals with male terminal ends
• Rectangular connector shape with no connector housing
• Black and gray plastic finish
• Cross-reference: Four Seasons 55223

Detailed Product Overview

Standard Ignition DS-647 is a headlight switch designed for vehicles that use a 6-terminal, blade-style electrical interface. The black and gray plastic construction, direct attachment method, and rectangular terminal layout support a straightforward replacement on GM trucks and SUVs from the early 1990s. This part number, DS-647, is listed across multiple interchange references and is suited for restoring headlight control when the original switch shows wear, intermittent operation, or electrical resistance. It is a practical replacement for Chevrolet C1500 and GMC K1500 platforms, as well as related Blazer and Yukon applications.

Common Problems This Part Can Address

• Headlights that do not turn on or respond inconsistently
• Intermittent lighting operation caused by worn internal contacts
• Excessive resistance in the headlight circuit
• Switch failure from age, heat, or repeated use
• Loose or unreliable dash-mounted headlight control

Installation Notes and Tips

Verify the terminal count, connector style, and vehicle year before installation. This DS-647 switch uses a direct, snap-fit attachment method and a 6-blade male terminal layout, so matching the original connector configuration is important for proper fitment. Confirm whether your application calls for the gray-specific 1990-1991 version or the broader 1992-1994 coverage before ordering. For best results, inspect the connector terminals and surrounding wiring for heat damage or corrosion during replacement.

Quality Assurance

Standard Ignition states that this switch is built with robust materials and copper alloy conductors, then tested for both mechanical action and electrical performance. That validation process supports consistent operation in service applications.