24V LED bulbs for indoor and outdoor use – Heavy-duty

The 24V interior/exterior LED for heavy goods vehicles cover many bases. For the cab interior: T10 W5W (dome light), festoons (trunk lighting), T4W BA9S (indicator). For the exterior: P21W BA15S (turn signals, reverse), P21/5W BAY15D (brake/position lights), H21W BAY9S (side turn signals), PY21W BAU15S (orange turn signals). Each base corresponds to a specific use and must be replaced with the same format in 24V LED. AGM Vision lists all these bases in 24V high-brightness LED version, with compatibility tested on the main truck brands.

To identify the bulb base of your heavy-duty vehicle, several methods exist. The simplest: remove the original bulb and read the reference written on the base or the glass (P21W, W5W, C5W, etc.). Otherwise, consult the vehicle manual, which lists all bulb types by location. You can also measure the size and shape of the base: bayonet (BA15S), wedge (W5W), festoon (length in mm). Watch out for variants: an orange turn signal uses a PY21W (offset base BAU15S) and not a P21W. AGM Vision indicates the compatible base on each product sheet.

The legality of 24V signalling LEDs depends on the type of light. Position lights and number plate lighting generally allow LEDs if the colour and intensity are compliant. For indicators, the LED must produce an orange light (not a white LED behind an orange lens). Brake lights must maintain sufficient intensity and a uniform red light. During the heavy goods vehicle roadworthiness test, the inspector checks visual compliance. AGM Vision recommends LEDs with a luminous flux close to the original in order to remain within regulatory tolerances.

Rapid flashing (hyperflash) is the most common problem when switching to LEDs on a truck. It happens because the flasher relay detects abnormally low power consumption and interprets this as a burnt-out bulb. Two solutions exist: install a 24V load resistor in parallel on each LED turn signal, or replace the flasher relay with an LED-compatible model. The second option is preferable, because it avoids resistor overheating. AGM Vision offers universal 24V flasher relays compatible with low-consumption LEDs.

The 24V LED signalling bulbs (turn signals, brake lights, reverse, position) last between 25,000 and 50,000 hours, compared with 1,000 to 2,000 hours for a conventional bulb. On a professional heavy goods vehicle running 10 to 12 hours per day, this represents several years without replacement. This advantage is crucial for transport fleets: fewer technical stops and increased safety, because the risk of driving with a burnt-out light is greatly reduced. LEDs also withstand the constant vibrations of heavy goods vehicles better thanks to the absence of a fragile filament.