In older M2s, a resistor pack is used for discrete speeds (Low, Med 1, Med 2, High). Newer models often use Pulse Width Modulation (PWM) to provide infinitely variable fan speeds.
Constant power is generally supplied from the under-hood PDM, specifically via a 30A fuse (often Fuse F2 on older models). Freightliner M2 Blower Motor Wiring Diagram
This module acts as the "brain," receiving signals from the HVAC control head and sending the appropriate command to the blower circuit. 2. Standard Wiring and Pinouts In older M2s, a resistor pack is used
