MDS w/ Alt. Posts & No Plate 55-002

OVERVIEW

When it comes to safeguarding your air-cooled investment, the QuickCar Racing Products Master Disconnect Switch with Alternator Posts is an absolute necessity for any serious VW enthusiast. Whether you are tearing up the dunes in a high-performance sand rail, competing in a sanctioned off-road race, or simply want an added layer of security for your restored vintage Beetle, this switch provides the ultimate fail-safe. Unlike standard two-post switches that only disconnect the battery, this four-post design includes dedicated alternator terminals. This is critical for air-cooled engines equipped with alternators, as it prevents the engine from continuing to run on the alternator''s internal circuit after the battery is disconnecteda common and dangerous phenomenon known as "run-on" that can lead to electrical fires or uncontrolled engine operation during an emergency.

Engineered for rugged durability and custom integration, the QRP 55-002 model comes without a pre-fabricated mounting plate, offering the ultimate flexibility for custom dashboard layouts and hidden security installations. The switch features a high-visibility, bright red epoxy-coated handle that ensures quick identification when seconds count. Constructed to meet the rigorous demands of professional racing organizations, this master disconnect switch utilizes heavy-duty 3/8-inch studs for the main battery cables and #10 terminals for the alternator circuit, ensuring a low-resistance connection that can handle the high cranking amps of a high-compression Volkswagen flat-four. At Appletree Automotive, we know that reliability is everything when you''re miles from civilization, and this QuickCar switch delivers the peace of mind that your electrical system is under your total control.

FITMENT

This Master Disconnect Switch is a universal component designed for 12V and 24V electrical systems. It is highly recommended for the following air-cooled Volkswagen applications and custom builds:

• Volkswagen Beetle (Type 1): All years and models, especially those converted to 12V alternator systems.
• Volkswagen Super Beetle: Ideal for high-performance street and strip builds.
• Volkswagen Karmann Ghia: Perfect for added electrical safety and theft prevention.
• Volkswagen Bus / Transporter (Type 2): Fits Bay Window and Split Window models with custom electrical setups.
• Volkswagen Thing (Type 181): Essential for rugged off-road and military-style builds.
• Volkswagen Type 3 (Squareback, Fastback, Notchback): Great for modernizing the electrical safety profile.
• Sand Rails & Dune Buggies: A requirement for most racing bodies and a safety staple for recreational railing.
• Baja Bugs: Designed to withstand the vibration and harsh environments of off-road desert racing.
• Meyers Manx & Kit Cars: Easily integrated into custom fiberglass dashes or chassis rails.

SPECS

• Manufacturer: QuickCar Racing Products
• Part Number: 55-002 (QRP55-002)
• Switch Type: Master Disconnect with Alternator Cut-Off (4-Post)
• Handle Finish: Red Epoxy Coated for corrosion resistance and visibility
• Mounting Hole Requirement: 3/4-inch (19mm)
• Battery Terminals: Two 3/8-inch-16 threaded studs (Accepts standard ring terminals)
• Alternator Terminals: Two #10-32 threaded studs (Prevents engine run-on)
• Mounting Plate: None (Designed for direct-to-panel or custom mounting)
• Voltage Compatibility: 12V - 24V DC systems
• Weight: Approximately 0.6 lbs

PRO TIPS

1. Eliminating Engine Run-On with the Alternator Circuit

One of the most common mistakes VW owners make is using a simple 2-post switch on an alternator-equipped engine. If you flip a 2-post switch while the engine is running, the alternator will continue to provide power to the ignition coil, and the engine will not stop. To wire this QuickCar 4-post switch correctly, you must run the small wire from the alternator (the field or exciter wire) through the two smaller #10 terminals on the back of the switch. When you turn the handle to the "off" position, it simultaneously breaks the battery connection and the alternator circuit, ensuring the engine dies instantly. This is a mandatory safety requirement for almost all track and off-road racing sanctioning bodies.

2. Strategic Mounting for Security and Safety

Since this model (55-002) does not include a mounting plate, you have the freedom to be creative with your placement. For a dedicated race car, mount it in a location reachable by both the driver and safety crews outside the vehicle. For a street-driven Beetle or Ghia, many of our customers mount this switch in a hidden location, such as under the rear seat near the battery or tucked behind the dashboard, to serve as a highly effective anti-theft device. Even if a thief manages to hotwire your ignition, they won''t be able to provide power to the starter or the coil without finding and engaging this master switch.

3. Use High-Quality Terminals and Heat Shrink

In the high-vibration environment of a VW engine bay or a sand rail chassis, electrical connections are the first thing to fail. When installing this switch, always use high-quality copper ring terminals that are properly crimped (and ideally soldered) to your 2-gauge or 4-gauge battery cables. Use marine-grade adhesive-lined heat shrink over the terminal barrels to prevent moisture from wicking into the wire strands, which leads to internal corrosion and voltage drop. Additionally, we recommend using QuickCar Part # 55-120 to jump current from the alternator to the battery post if your specific wiring diagram calls for a shared charging/output path.