Inside Rear View Mirror - Auto-Dimming Function Verification Test
|Publication Date:||1 January 2014|
Note: Nothing in this standard supercedes applicable laws and regulations.
Note: In the event of conflict between the English and domestic language, the English language shall take precedence.
Purpose. Functional verification test of the automatic dimming feature of the Inside Rear View Mirror (ISRVM).
Note: This GMW is not intended to be a validation test of our Component Technical Specifications (CTS), as the supplier is engineering responsible for component level validation (Level III Supplier Integration). As such, each subsequent program with usage of an auto-dimming ISRVM is NOT expected to perform this GMW to verify the autodimming ISRVMs functionality. The ISRVMs autodimming reflectance requirements (CTS) are documented in GMW16159.
The purpose of this GMW is to provide a simple procedure to confirm basic auto-dimming ISRVM functionality if it is ever questioned in a vehicle assembly plant, in a dealership, during proving grounds vehicle level testing, or vehicle electricalbench testing to protect against and/or to detect a quality spill.
Foreword. The auto-dimming (variable reflectance) feature detects forward and rear light conditions and then adjusts the reflectance level of the mirror to eliminate unwanted rear glare by the use of two photoelectric sensors. The reflectance level is variable and is dependent on the amount of rear glare in relationship to ambient conditions. Any light source viewed in the rear view mirror can be considered glare during nighttime conditions.
When the forward-facing Ambient Light Sensor (ALS) detects daytime conditions, the rearwardfacing "glare" sensor is inactive and the mirror remains in a high reflectance mode.
When nighttime conditions are sensed by the forward sensor, the rear-facing sensor is active and detects glare from rearward approaching vehicles and/or other glare producing light sources. The mirror will automatically adjust to a lower variable reflectance mode to remove the unwanted glare from the inside rear view mirror. The mirror will automatically return to a high reflectance mode whenever the vehicle is placed in REVERSE to ensure an improved view when backing up.
Note: During normal operation, do not allow the forward-facing or rearward-facing sensors to be obstructed, since this may impair proper performance. This "keep out zone" Field of View (FOV) for both the ALS and glare sensors are documented as reference layers (30 and 31, respectively) in the 3-dimensional (3D) UniGraphics component math data for all ISRVM part numbers.
Applicability. This procedure applies to all
passenger cars, light duty trucks, and medium duty trucks having
auto-dimming (i.e., ElectroChromic (EC), or variable-reflectance
Remarks. The GM Global Corporate Common Component (CCC) automatic dimming inside rear view mirror does not have a Light Emitting Diode (LED) status indicator or On/Off button interface like the typical automatic dimming ISRVMs have had in the past.