Circuit Description
WARNING: This page is about a different car, the 2004 Toyota Camry Solara. However, it is still accessible from the selected car via links, so may be relevant.
The blower motor is operated by signals from the A/C amplifier assy. Blower motor speed signals are transmitted by changes in the duty ratio.
Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, A is the period of continuity in one cycle, and B is the period of non-continuity.
The blower motor controller controls the blower motor speed.