How to Fix Heater in Car? The heating system in the car is essentially a motor-driven fan that blows warm air from the engine area to the inside. The system is fairly simple and rarely fails. The only defect that is likely to occur is when the fan ceases to function due to a break in the electrical circuit. A feed wire from the fusebox to the on/off switch on the dashboard or centre console, and another wire from the switch to the heater motor, make up this circuit. A separate wire normally connects the motor to the body.
In most cars, the heater motor is located beneath the centre of the dash, making it difficult to access. In some situations, however, the engine is located beneath the hood near the rear of the bulkhead. A blown fuse is the most typical source of any problem. This is usually in the main fusebox, however, it could be an in-line fuse wired into the motor’s feed. Check your workshop handbook for the precise location of the fuse. If it protects additional circuits that have also ceased working, the problem should be resolved by installing a new fuse.
How to Fix Heater in Car?
1. Check the Wiring to Fix Heater in Car
Check for loose, filthy, trapped, or disconnected wires if replacing the fuse does not fix the problem, or if the other components controlled by the fuse are operating. Use your workshop manual wiring diagram to locate the heating wires. Check each connection as you follow the wires as far as possible.
2. Check Earth
Check the heater motor’s ground connection if no damaged wires are found. This is normally found on the bulkhead and may have deteriorated. Clean any corrosion from the mating surfaces using wet or dry paper before refitting the fastening nut or screw and ensuring it is tight. Vaseline the connection to prevent further corrosion.
3. Checking a Heater Fan Circuit
All of your tests should be performed with the clip of your test light earthed. Start the engine and turn on the fan. Disconnect the motor feed wires (a multi-connector plug is used here) and probe the terminals. If the lamp illuminates, the current is present, and the motor is most likely malfunctioning. If the lamp fails to illuminate, check the switch.
Remove the switch from the dash and, while it is still turned on, probe the output terminals. If the lamp illuminates, the wiring between the switch and the motor is defective. And if it doesn’t, check the switch input terminal as well. If the lamp illuminates, the switch is faulty. If it doesn’t light, check the fusebox for power.
With the lamp, check the fuse output terminal. If the lamp does not illuminate, replace the fuse and try again. If the lamp illuminates but the heater still does not operate, the wiring between the fusebox and the switch is broken.
4. Use Test Lamp
A circuit tester is required to inspect the motor windings. This is comparable to a test lamp, however, it runs on its own battery.
Disconnect the battery and the motor cables, making a note of how they fit. Connect one side of the tester to the motor earth wire and probe each feed terminal one at a time. If the tester illuminates all of the terminals, the motor is operational. However, if the tester fails to light, the motor has blown and must be replaced.