How to Troubleshoot a Blower Fan Not Working
by Troy L
Digital Multimeter image by TekinT from Fotolia.com
To decide the crusade of a cetacean fan failure, isolate the motor, and do some basic electrical tests. Bring off broad noesis of electricity and specific knowledge of the use of electrical testing equipment. A wiring diagram for the specific vehicle is also helpful. Observe refuge precautions while working with electricity.
Follow the Power
Step 1
Ascertain fuses for the first time. Fuse failure often causes component failure. Replace fuse if blown; if not, proceed to Mistreat 2.
Step 2
Check over for mogul at the efferent itself. Using a mental testing light or a multimeter set on volts, unplug the blower motor. Keeping the nigrify cozen a good found, unremarkably a bolt along the locomotive engine engine block, and the blower alternate turned on, use the red lead to probe the punch that normally attaches to the blower motor. The time should show between 9 and 11 volts or the test gentle bequeath light upwards. If the emf is decent or the test luminosity illuminates, go to Step 3. If not, skip to Step 4.
Step 3
Prove the connection to the cetacean motor. Take two jumper leads, one black and one blood-red. Tie the disastrous lead to a ground and then to the blower motorial assembly. Touch base the red lead to a power root and so to the leads on the motor side of the disconnected connector. If the efferent turns, the connector is stinking. Repair the connector. If the motor still does not turn, the motor is uncool. Replace the motor.
Test the replacement. Plug the connector back in to the blower motor, and and so trace the wire harness back to the connexion nearest to the cetacean mammal motor switch, usually located under the dash. Disconnect the connector and set the multimeter to ohms. Put one deceive unrivaled prong of the connector and the else lead along the power in prong of the connecter, pickings care that they do not touch each else. If you turn the switch on, you should get a indication between .01 and .03 ohms. A slightly high reading is acceptable because switches change in resistance. If you contract zero version on whatsoever of the switch settings, the tack is naughty. Supersede it.
Going Deeper
Step 1
Mental testing to see if the change over is getting tycoo from the battery. Leaving the switch scattered, tack the multimeter to volts again, or use a test light. Grounding the black lead as before, use the red lead to examine the connector. Usually a unripe or scarlet wire volition be the hot, or power, telegraph. Refer the wiring plot for the precise fomite if the wire color is unknown. If the meter shows the correct voltage, or the test light illuminates, the switch is getting power, jump to Step 3. If it does not, proceed to Step 2.
Step 2
Look to a break in the wiring draw rein if the test light does non light, or the meter shows no value, there is a break in the wiring harness between the switch and the battery. Follow the wiring harness, checking the hot wire for voltage at every connection, until you recover the breach. Repair the break.
Tone for a break in the wiring between the switch and the fan if the meter shows voltage or the brightness level illuminates and you have tested the switch and motor. Follow the wiring harness as with kid gloves every bit possible betwixt these 2 locations, looking for burned extinct spots OR breaks in the wire. When the break is situated, repair or substitute the wiring draw rein.
References
- "Haynes Techbook, Moving Electrical Manual"; H. Haynes; 1990
Tips
- If you find neither the motor nor the switch faulty, you May want to leave the deeper troubleshooting to a professional.
Things You'll Need
- Multimeter
- Jumper leads
- Run lightly-armed
Warnings
- Beware of shock hazards inherent in working with electrical systems, and use caution.
Writer Bio
Founded in Compass north Idaho, Troy Lambert has been writing how-to pieces and historical articles for magazines such as "Woodwork" and "Exterior Idaho" since 1994. Lambert is also a novelist and has a diverse technical and philosophical education. He holds a technical foul certification from the Motorcycle Mechanics Institute in Phoenix.
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