How to Read a Truck LED Lamp Specification Sheet Before You Order

A truck lighting specification sheet is short, often only a handful of lines, and it is easy to accept one without reading it properly. The fields that matter fall into three groups: those that define whether the lamp fits, those that define whether it lasts, and those that are descriptive rather than engineering.

Fields that determine fit

• Voltage. The supply the lamp accepts. Confirm it covers the vehicle system you are fitting it to, including cranking transients.
• LED quantity. A useful proxy for output and, more importantly, a proxy for the size of the emitter array. Lamps in the same function with very different LED counts are generally intended for different mounting positions and different brightness requirements.
• Lens material. Polycarbonate is the standard for impact-exposed positions. Confirm it for anything mounted low on a trailer or at the rear.
• Housing material. ABS plastic for sealed signal and marker assemblies. Die-cast aluminium for work lamps, where the housing must dissipate heat from sustained high output.
• Colour. Where the lamp performs more than one function, confirm which colour serves which function.

Fields that determine service life

• Sealing rating. State the requirement from the operating environment rather than accepting the model default.
• Mounting method. Surface mount, grommet mount, or bracket-mounted with a specified bracket material. Bracket material matters on tail lamp assemblies where the bracket carries mechanical load.
• Connection. Hard-wired with pigtail, a standard two-pin plug, or a specific connector. Confirm against your harness, because this is a change that cannot be made on arrival without cutting and re-terminating.

Fields that describe rather than specify

Phrases such as low power consumption, multi-function design, easy bolt-on installation and compact and lightweight appear across commercial lighting catalogues. They are not wrong, but they are not specifications either. Two different suppliers can both claim low power consumption while supplying products with materially different current draw.

The way to convert these into a comparison is to ask for the figure behind the claim: actual current draw in watts or milliamps at the rated voltage, the actual lens and housing material, and the actual mounting hardware supplied with the lamp.

Fields that are only comparable across a range

Carton figures, specifically quantity per box, quantity per carton and carton size, are meaningful when comparing suppliers at the same order quantity, because they determine how the order divides and how it is shipped. They are less meaningful in isolation.

A short checklist

• Model number and function confirmed against the mounting position.
• Voltage confirmed against the vehicle system, with transient margin.
• Lens and housing material appropriate to the position and environment.
• Sealing rating appropriate to the operating environment.
• Connection type and mounting method confirmed against your harness and bodywork.
• Colour combination confirmed for multi-function positions.
• Carton data received, for freight calculation and receiving planning.
• Certification set confirmed for the destination market.