Dongguan ,Guangdong,China-September 16, 2026
The temperature and humidity resistance test method for vehicle lights is mainly based on the requirements of “5.2 Damp heat cycling test” in the standard GB/T 10485-2025 Road vehicles – External lighting and light signaling devices – Environmental durability. Below, we will learn about this test method.
Test equipment: Huanyi Instruments GB/T10485 Automotive Signal Lighting Temperature and Humidity Test Chamber
Standard met: GB/T 10485-2025 Road vehicles – External lighting and light signaling devices – Environmental durability
Test samples: 2 lighting devices or 2 light signaling devices.
Test Method:
1. The sample is not illuminated during the test.
2. Initial measurements of photometric value change and sealing test are performed on the sample.
3. The sample is placed in the test chamber in a simulated normal loading position for testing.
4. Each test cycle is 720 minutes, including the following process (see figure below).
a. Heating Process 1: Temperature rises from 23℃ to 80℃, relative humidity rises to 80% (for Category L vehicle lights, the permissible temperature rise is from 23℃ to 60℃, relative humidity rises to 80%), heating time is 60 minutes.
b. Damp Heat Process: Maintain temperature at 80℃ (for Category L vehicle lights, the permissible temperature maintenance is 60℃), relative humidity at 80%, duration is 240 minutes.
c. Cooling Process: From 80℃ (for Category L vehicle lights, the permissible temperature maintenance is 60℃), relative humidity at 80%, cool down to -40℃. When the temperature drops to 20℃, the relative humidity should be 20%~50%. When the temperature is below 10℃, humidity is not required. Cooling time is 120 minutes.
d. Maintain Low Temperature: -40℃, time is 240 minutes.
e. Heating Process 2: Raise the temperature to 23℃ over 60 minutes, maintaining relative humidity between 20% and 40% from 10℃ onwards.
For devices with front lighting functionality, conduct 8 cycles according to the above “Cycle Chart” requirements; for devices with only light signal functionality, conduct 4 cycles according to the “Cycle Chart” requirements.
5. After the cycle tests are completed, retest the sample for photometric value changes and sealing.
Result Judgment:
After the test, visual inspection should reveal no discoloration of the sample, and no deformation or bubbling should be observed in the reflector and lens. The change in photometric value after the initial and subsequent retests should be less than 20%. During the retesting of the sealing test, visual inspection should reveal no bubbles at the bonding, welding, and connection points of the sample.
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Dongguan Huanyi Instruments Technology Co., Ltd. was established on March 20, 2007, covering an area of 6,022 square meters. It is a high-tech enterprise integrating R&D, production, sales and after-sales service. It participated in the drafting of national standards and industry standards for environmental simulation test equipment.
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