Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Blower Control
When air conditioning (A/C) is selected or the blower speed is manually selected, the automatic temperature control (ATC) module energizes the coil of the blower relay in the battery junction box (BJB). The energized blower relay supplies battery power to the blower motor, which is grounded through the blower control module. The speed of the blower is controlled by a pulse width modulation (PWM) signal from the automatic temperature control (ATC) module to the blower control module. The blower control module regulates the blower motor voltage in relation to the pulse width modulation (PWM) signal.
When the blower is in the automatic mode the automatic temperature control (ATC) module determines the blower speed required from the comfort algorithms. When the blower is in the manual mode, the automatic temperature control (ATC) module operates the blower at one of seven fixed speeds as selected on the control panel.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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