Description
HERTH+BUSS ELPARTS 89901134 Brake Tail Light Bulb | T4W | 24V | 4W | BA9s | Ships Today
The HERTH+BUSS ELPARTS 89901134 brake tail light bulb is a 24V T4W rated at 4 watts power consumption. The BA9s single contact socket ensures compatibility with standard commercial vehicle brake light, tail light, and instrument panel fittings. This HD (heavy duty) version offers increased vibration resistance for demanding commercial vehicle applications. At £1.99, the HERTH+BUSS ELPARTS 89901134 brake light bulb restores legal lighting compliance for trucks, trailers, buses, and other 24V commercial vehicles.
What Is the HERTH+BUSS ELPARTS 89901134 Brake Light Bulb?
The Role of a Brake Light Bulb
A functioning brake light is a mandatory safety requirement on any vehicle used on UK and EU roads. Brake lights illuminate when the driver applies the brakes, warning following traffic of deceleration. According to UK Government vehicle lighting regulations, all brake lights are inspected during annual tests.
What This Bulb Includes
The HERTH+BUSS ELPARTS 89901134 brake light bulb is a T4W type with 4 watts at 24 volts. The BA9s socket features a single contact pin and bayonet fitting. The HD (heavy duty) version features reinforced construction for increased durability in high-vibration commercial vehicle environments.
For technical information on commercial vehicle lighting, refer to Bosch automotive lighting documentation.
Full Specifications
| Specification | Detail |
|---|---|
| Item Number | 89901134 |
| Manufacturer | HERTH+BUSS ELPARTS |
| Lamp Type | T4W |
| Voltage | 24V |
| Rated Power | 4W |
| Diameter | 8.5 mm |
| Height | 28.4 mm |
| Version | HD (Heavy Duty) |
| Socket Type | BA9s |
| Condition | New |
| EAN | 4026736078171 |
| Trade Number | HERTH+BUSS ELPARTS T4W |
Vehicle Compatibility
The HERTH+BUSS ELPARTS 89901134 brake light bulb fits any 24V vehicle requiring a T4W bulb with BA9s socket. Before ordering, confirm your vehicle uses a 24V electrical system and the socket type is BA9s.
If uncertain about fitment, our parts team can assist before you order.
Common Applications
| Vehicle Type | Typical Use |
|---|---|
| Trucks (24V) | Brake light, tail light |
| Trailers (24V) | Rear position light |
| Buses and coaches | Instrument panel, marker light |
| Construction machinery | Indicator, warning light |
Cross-Reference
| Reference | Number |
|---|---|
| Part Number | 89901134 |
| Trade Number | T4W |
| Socket | BA9s |
| Version | HD |
Why Choose This Bulb
24V Commercial Vehicle Specification
The HERTH+BUSS ELPARTS 89901134 brake light bulb is designed for 24V electrical systems — the standard for heavy goods vehicles, trucks, buses, and commercial trailers.
BA9s Socket
The BA9s socket is a standard fitting for T4W bulbs in commercial vehicle brake light, tail light, and instrument panel applications.
HD Heavy Duty Version
The HD designation indicates reinforced construction for increased vibration resistance. Commercial vehicles generate significant vibration during normal operation. Standard bulbs fail prematurely in these conditions. This HD bulb lasts longer.
4W Power Output
At 4 watts, the T4W provides adequate illumination for brake light and tail light functions with minimal current draw.
Compact Dimensions
At 8.5mm diameter and 28.4mm height, this bulb fits into tight instrument panel and light housing spaces.
Installation
The HERTH+BUSS ELPARTS 89901134 requires no tools for installation:
Access the rear of the light housing or instrument panel
Remove the old bulb by pulling or twisting counter-clockwise
Insert the new bulb into the BA9s socket
Push and twist clockwise until it locks into place
Test the light before reassembling
Always handle bulbs with clean hands or use a cloth. Oil from skin creates hot spots and reduces bulb life.
For lighting maintenance guidance, consult HELLA commercial vehicle lighting resources.
Frequently Asked Questions for HERTH+BUSS ELPARTS 89901134 brake
Q: Does this bulb work on 12V vehicles?
No. This bulb is designed for 24V systems only. Using on 12V will produce dim output.
Q: What does HD version mean?
Heavy Duty. Reinforced construction for increased vibration resistance in commercial vehicles.
Q: What is the difference between T4W and R5W?
T4W is 4 watts, typically used for brake and tail lights. R5W is 5 watts, typically used for tail and marker lights. Check your vehicle specification.
Q: Is BA9s the same as BA9?
Yes. BA9s (single contact) is the standard designation for this socket type.
Q: Does this fit instrument panel lights?
Yes, many commercial vehicles use T4W BA9s bulbs for dashboard illumination.
Q: What is the warranty?
HERTH+BUSS ELPARTS typically provides 12 months warranty.
Q: Does this ship today?
Yes. Orders before 2pm GMT ship same day.
Buy the HERTH+BUSS ELPARTS 89901134 Brake Light Bulb
Add to basket for same-day dispatch. Fast UK and EU delivery available. Contact our parts team for bulk orders.
Price: £1.99 | HERTH+BUSS ELPARTS | T4W | 24V | 4W | BA9s | HD Heavy Duty | New | In Stock | Ships Today





