Memory Mirrors Operation

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The memory mirrors are controlled by the mirror position sensors, the driver door switch assembly (DDSA), and the front door modules. The DDSA decodes memory switch activations while the mirror position sensors provide mirror position information to the front door modules. The front door modules supply voltage and ground to the mirror position sensors, store mirror position information, and apply voltage and ground to run the mirror motors.

For memory operations, each outside rearview mirror has four additional circuits and contains a vertical position sensor and a horizontal position sensor. The position sensors, which are potentiometer type sensors, are attached to the corresponding position motor of each mirror, and provide constant information, in the form of feedback voltage to the associated door module to indicate the vertical and horizontal position of the mirror. Each position sensor of each mirror is wired to the corresponding front door module through four circuits to provide mirror location information in the following manner. Each front door module supplies 5 volts reference voltage through a 5 volt reference circuit, and ground through a mirror sensor low reference circuit, to both of its position sensors. Each front door module also supplies 5 volts through the vertical position sensor signal circuit, and, 5 volts through the horizontal position sensor signal circuit, to the corresponding position sensor. When the mirror motors run, the resistance of the attached sensors vary, which in turn, varies the feedback voltage to the door module. Feedback voltage for each sensor varies between 0.25 volts and 4.75 volts.

When mirror positions are programmed into the personalization package, the front door modules store the positions indicated by the feedback voltages of the position sensors. When a memory recall is requested, the door modules compare the feedback voltages indicated by the current mirror positions to the stored feedback voltages. The door modules then move the mirrors until the current feedback voltages match the stored feedback voltage levels.