Brake Light Switch, 3 Post, Fits Beetle, Bus, Ghia & Buggy

Product Overview

When it comes to the safety and functionality of your vintage air-cooled Volkswagen, few components are as critical yet overlooked as the brake light switch. This premium 3-post brake light switch is engineered to provide reliable, instantaneous activation of your rear stop lamps the moment you apply hydraulic pressure to the pedal. Designed for the dual-circuit master cylinders found in later-model Beetles, Buses, and Ghias, this switch serves a dual purpose: it completes the circuit for your brake lights and integrates with the dashboard warning light system to alert you of pressure differentials within the braking system. Whether you are navigating heavy modern traffic or cruising a backroad in your weekend warrior, ensuring your intentions are visible to drivers behind you is paramount. This EMPI-sourced component is built to withstand the rigors of daily driving, featuring a robust internal diaphragm and high-quality contact points that resist the arcing and pitting common in inferior aftermarket alternatives.

Installation is straightforward for the seasoned DIY mechanic or the professional restorer alike, as this switch is designed to screw directly into the stock master cylinder ports. It is particularly essential for owners of custom dune buggies and sand rails utilizing the popular Type 2 master cylinder conversion, providing a clean, factory-style solution for brake light integration. The 3-post configuration is the specific requirement for vehicles produced during the 1970s, where the third terminal facilitates the brake failure warning lamp circuita vital safety feature for dual-circuit systems. By choosing this high-performance switch from Appletree Automotive, you are investing in a part that meets or exceeds original equipment specifications, ensuring that your classic VW''s electrical and hydraulic systems remain in perfect harmony. Don''t let a flickering or dead brake light compromise your safety or lead to a fix-it ticket; upgrade to a switch that provides the peace of mind you deserve.

Vehicle Fitment

• Volkswagen Beetle (Type 1): 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979
• Volkswagen Super Beetle: 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979
• Volkswagen Bus (Type 2): 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979
• Volkswagen Karmann Ghia: 1970, 1971, 1972, 1973, 1974
• Custom Applications: Fits Dune Buggies, Sand Rails, and Manx-style shells using Type 2 or late-model Type 1 Master Cylinders.

Technical Specifications

• Part Number: 113-945-515G
• Terminal Count: 3-Post (Male Spade Terminals)
• Activation Type: Hydraulic Pressure Sensitive
• Thread Pitch: M10 x 1.0 (Compatible with most standard VW Master Cylinders)
• Thread Type: Metric (Also fits many 1/8 inch NPT pipe thread applications common in aftermarket cylinders)
• Material: Zinc-Plated Steel Housing with High-Impact Composite Insulator
• Voltage Compatibility: 12-Volt Systems (Standard for 1970+ models)
• Circuit Function: Normally Open (Closes upon hydraulic pressure application)

Pro Tips from the Specialist

Tip 1: Bleeding Air is Non-Negotiable

Whenever you replace a brake light switch, you are introducing a small amount of air directly into the master cylinder. After threading the new switch in, it is absolutely vital that you bleed the braking system, starting with the wheel cylinder or caliper furthest from the master cylinder. If air is trapped directly underneath the switch diaphragm, you may experience a "spongy" pedal or, more commonly, a significant delay in your brake lights turning on. In some cases, the lights may not turn on at all until the pedal is pushed halfway to the floor. Always verify that the lights trigger with even light foot pressure before taking the car out on the road.

Tip 2: Terminal Identification and Wiring Care

The 3-post switch is unique because of that third terminal used for the dashboard warning light. When swapping out your old switch, take a moment to clean your wire ends with a bit of electronic cleaner or a light abrasive. If your plastic terminal covers are cracked or missing, replace them to prevent accidental grounding against the master cylinder body. Ensure the wires are pushed firmly onto the spades; a loose connection here is the leading cause of "phantom" brake light failure where the lights work intermittently. If you are converting an older car to a dual-circuit system, ensure you reference a 1970+ wiring diagram to utilize the third post correctly.

Tip 3: Avoid Over-Torquing the Switch

While it is tempting to "crank down" on the switch to ensure a leak-free seal, the master cylinder is often made of cast material that can stress or crack if the tapered threads are over-tightened. This switch uses a standard M10x1.0 thread. You should thread it in by hand first to avoid cross-threading, then snug it down with a wrench until it is firm. You do not need thread sealant or Teflon tape on these; the metal-to-metal contact of the threads provides the seal. Using tape can actually insulate the switch or get bits of debris into the hydraulic lines, which can lead to catastrophic brake failure or clogged valves.