Collection: Indicator Lights & Dashboard (T3, T4.2, T4.7...)

T3, T4, T5, T6.5: how to choose the right size

The designation T (for Tubular or Tiny) follows a simple logic: the letter identifies the wedge base format without an external base, and the number indicates the glass diameter in millimeters × approximately 0.8. More precisely:

• T3 = 3 mm diameter — the smallest, for thin indicator lights and discrete signal indicators.
• T4.2 = 4.2 mm diameter — intermediate dashboard indicator lights.
• T4.7 = 4.7 mm diameter — gauge lights and key warning lights.
• T5 = 5 mm diameter — the most universal, found on most modern dashboards.
• T6.5 = 6.5 mm diameter — specific indicator lights for certain premium dashboards.

The T5: the ultimate dashboard bulb

With its 149 references in our catalog, the T5 is by far the most widely used dashboard bulb. You will find it in:

• The speedometer and tachometer
• The engine temperature gauges and oil level gauges
• The car radio and its backlight
• The climate control and heating controls
• Certain warning lights (oil, battery, level, ABS)

Available in 1.2W halogen (the standard version) and LED with different color temperatures (neutral white, cool white, amber, blue, red).

Switching to LED on the dashboard

Switching dashboard indicator lights to LED offers several advantages: purer white light, possibility to customize the interior ambient color (red, blue, green, amber), extended lifespan, and reduced consumption. An aesthetic change that immediately modernizes the appearance of the dashboard.

An important precaution: some recent vehicles use directional LEDs (with polarity). If the LED does not light up after installation, remove it and reinsert it rotated 180° — the insertion direction matters. On older vehicles with original halogen bulbs, polarity is not an issue.

Finding the right reference

To identify the T compatible with your vehicle, gently remove the defective bulb (tweezers or flat screwdriver) and read the marking engraved on the base or the glass — the T dimension is usually indicated there. Otherwise, measure the glass diameter with a caliper: 3 mm = T3, 5 mm = T5, etc.