How To Fix Car Heater Not Working? 5 Easy Steps!

Are you wondering how to fix car heater not working? Check the wiring, the motor earth connection, and the heater fan circuit. Next is to use a test lamp that finds a motor feed. Afterward, test the motor windings the same as the test lamp but with a specific battery power supply.

Disconnect the wires and the battery in the motor and see just how exactly they fit. Failure to see the light in the engine using a tester then requires replacement.

how to fix car heater not working

It would help fix the car heater for twenty minutes to two hours, and the device will work just fine. The good thing is you can perform it at home with no special tools required. Let us discuss more on this below. Keep reading, my dear friends!


Steps To Fix Car Heater Not Working

Below are steps to help you fix your car heater in the correct way possible:


Step #1. Checking the wiring

Check for dirt, disconnected or trapped wire if a new fuse fails to solve the issue after you fit. See also if the other sections are working as controlled by the fuse. Observe the location of the heater wires from the manual wiring diagram. Check every connection and follow the wires as much as you can.


Step #2. Checking the motor earth

Check the motor earth if you see no damaged wires around, as this is located in the bulkhead that gets rusted. Remove any possible corrosion on mating surfaces using dry or wet paper and fit the screw or screwing nut again so that it is tight. Use the vaseline when you cover the connection preventing further corrosion.


Step #3. Checking the heater fan circuit

Use an earthed clip of a test lamp when you decide to perform the tests. Switch on the car fan after you turn the ignition. Disconnect the motor wires while you also probe its terminals. A faulty motor is the cause of a lamp that lights. Test its switch if the lamp does not light up correctly. Pull its control from the dash and let it stay switched, as you probe its output terminals. A lamp that lights would mean faulty wiring between the motor and switch. Check its switch input terminal if it does not light up properly.

A lamp that lights also would mean a broken regulator. Check its fuse box current if you see it does not light up correctly. Next is to probe the output terminal under the lamp so that if the latter does not light up correctly, try it again and alter the fuse. A working lamp light opposite to a dysfunctional heater would mean wiring in the switch and fuse box is faulty.


Step #4. Using a test lamp

Utilize the test lamp if there’s no issue with the wiring to see any sign of motor feed. Connect the last part of the test lamp to another earthing point and disconnect the wires or feed wire in the motor. See the multi-connector plug or the individual connections and turn the ignition on while pushing the motor switch to an on position. Then, probe the wire using a test lamp. The current already reaches the point when the lamp lights. Turn the heater switch on again in another position. The issue is with the motor itself if you see lights are on both wires.

Check the switch connections if no power is visible in the motor. Switch from the low up to high speeds after probing the output terminals. A broken engine result from the test lamp lights up in the output terminals. That’s when you need to seek expert advice. Check its input terminal if the lamps have failed to light. A faulty switch occurs if this lights up the test lamp. It will help call an auto-electrician if the test lamp does not illuminate when it touches the input terminal. It would mean that the wiring between the switch and fuse box is also faulty.


Step #5. Testing a motor

Check the car heater’s windings using a circuit tester, same as the test lamp but with a battery power supply. Disconnect the wires and battery connected in the motor that lets you see how it fits. Attach the tester’s side to the earth wire; follow it with proving both the feed terminals. The sound is a motor if the tester lights on airports. If the engine does not light with the tester failure, it needs replacement. You may also want to read about what is circuit tester.


Causes Of A Car Heater Malfunctioning

Learn to know these causes below in why a car heater is malfunctioning before you learn how to fix car heater not working:

  • Faulty switching system;
  • Choked cabin air filter and airflow restricted in the heater core;
  • Dysfunctional thermostat valve; and
  • Clogged heater core.


It’s A Wrap!

Now you’ve learned the steps on how to fix car heater not working. It’s relatively easy to set it up, provided with the tools needed. But more than that, it helps to learn the causes of a car heater malfunctioning like the clogged heater core, dysfunctional thermostatic valve, choked cabin air filter, and faulty switching system. Click on these links to read related articles; know burning smell in a car when heater is on and how much it cost to fix car heater.

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