/live/media/VE/VE_BS4521_Fro.jpg)
OE Quality
60-Day Returns
Calorstat BS4521 Brake Light Switch
Brake Light Switch for GM and Saab Applications
Calorstat BS4521 is a brake light switch with an M12x1.5 thread size, built for direct replacement in select Pontiac and Saab applications. It is a fitment-based electrical switch used to signal brake pedal movement and activate the rear stop lamps.
Key Features
- Brake light switch for electrical and body system repair
- M12x1.5 thread size for specified applications
- Direct-fit replacement for select Pontiac GTO and Saab 900 models
- OE supplier context from Vernet/Calorstat for GM applications
- Part number BS4521 for catalog and cross-reference lookup
Detailed Description
Calorstat BS4521 is a brake light switch used in stop lamp circuit operation, helping restore proper brake pedal signal output when the original switch is worn or inconsistent. This part is listed for 2004 Pontiac GTO and Saab 900 applications from 1981-1988 and 1993-1994. For buyers searching for a 2004 Pontiac GTO brake light switch or a Saab 900 brake pedal switch, BS4521 provides a fitment-specific replacement option with an M12x1.5 thread.
This part cross-references Bosch 0 986 343 003 for the same application.
What It Helps Fix
- Brake lamps that do not illuminate when the pedal is pressed
- Intermittent stop light operation
- Delayed or inconsistent brake pedal switch response
- Faults related to the brake light circuit on select Saab 900 and Pontiac GTO vehicles
- Replacement needs for a worn M12x1.5 threaded brake switch
Installation Notes and Tips
Verify thread size and connector match before installation. Confirm vehicle year and model against the listed fitment: Fits 2004 Pontiac GTO, N/A; Fits 1993-1994 Saab 900, N/A; Fits 1981-1988 Saab 900, N/A. After installation, test brake lamp operation and pedal switch function before returning the vehicle to service.
Quality Assurance
Calorstat, also known as Vernet in OE supply channels, is identified as an OE supplier to GM for the listed applications. Use the BS4521 part number when matching the correct brake light switch for Pontiac GTO and Saab 900 fitment.
| Brand | Calorstat |
|---|---|
| Part Number | BS4521 |
| Thread Size | M12x1.5 |
This part fits 11 vehicles. Search below:
| Year | Make | Model | Body Type | Liters | Cylinders | Position | Notes |
|---|---|---|---|---|---|---|---|
| 2004 | Pontiac | GTO | 5.7L | V8 | N/A | Vernet is an OE Supplier to GM | |
| 1994 | Saab | 900 | Convertible | 2.5L | V6 | N/A | Vernet is an OE Supplier to GM |
| 1993 | Saab | 900 | N/A | Vernet is an OE Supplier to GM | |||
| 1988 | Saab | 900 | N/A | Vernet is an OE Supplier to GM | |||
| 1987 | Saab | 900 | N/A | Vernet is an OE Supplier to GM | |||
| 1986 | Saab | 900 | N/A | Vernet is an OE Supplier to GM | |||
| 1985 | Saab | 900 | 2.0L | L4 | N/A | Vernet is an OE Supplier to GM | |
| 1984 | Saab | 900 | 2.0L | L4 | N/A | Vernet is an OE Supplier to GM | |
| 1983 | Saab | 900 | 2.0L | L4 | N/A | Vernet is an OE Supplier to GM | |
| 1982 | Saab | 900 | 2.0L | L4 | N/A | Vernet is an OE Supplier to GM | |
| 1981 | Saab | 900 | 2.0L | L4 | N/A | Vernet is an OE Supplier to GM |
* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.
This part directly replaces or is cross-referenced with the following part numbers:
Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.