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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSFORD1999TAURUS V8-3.4L VIN N SHOREPAIR AND DIAGNOSISHEATING AND AIR CONDITIONINGCONTROL MODULE HVACDESCRIPTION AND OPERATION
1999 Ford Taurus V8-3.4L VIN N SHO
Control Module HVAC: Description and Operation
1999 Ford Taurus V8-3.4L VIN N SHOSECTION Description and Operation
The A/C blower motor speed control is a Pulse Width Modulated (PWM) type which provides variable blower speed control of the blower motor. The A/C blower motor speed control is controlled by switching the control signal voltage of 5 volts OFF and ON, 2,000 times per second. By varying the ratio of time on (+5 volts) to time off (0 volts), the Electronic Automatic Temperature control (EATC) module tells the A/C blower motor speed control how fast the blower motor should run. The A/C blower motor speed control has the following features:
- Controls the speed of the blower motor by switching the motor OFF and ON 40,000 times per second by varying the ratio of time ON (+14 volts) to time OFF (0 volts).
- Has circuitry to protect the blower motor from burning out in the event of a locked rotor condition.
- Can compensate for changes in battery positive voltage (B+) which prevents the blower speed from slowing down when the engine is idling and will provide up to a maximum of 30 amperes for blower motor operation with battery voltages between 10 and 16 volts.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.