Troubleshooting electrical equipment (BMW 3 Series E46)

Note: Faults related to the starting system are listed under the heading "Engine" (see above in this section).

The battery runs out in a few days

• Internal battery failure (chapter 5A).
• Loose or corroded battery terminal clamps ("Weekly check").
• Worn or incorrectly installed accessory drive belt (chapter 1).
• No charging from the generator with its normal output parameters (chapter 5A).
• Generator or voltage regulator failure (chapter 5A).
• Short circuit causing battery discharge (chapter 5A and 12).

Ignition/Battery Discharge Indicator Does Not Go Out When Engine Is Running

• Worn or incorrectly installed accessory drive belt (chapter 1).
• Worn, stuck or dirty generator brushes (chapter 5A).
• Broken or weakened generator brush springs (chapter 5A).
• Internal fault in the generator or voltage regulator (chapter 5A).
• Open, disconnected or loose contacts in the charging circuit (chapter 5A).

Ignition/Battery Discharge Indicator Does Not Light When I Turn On the Ignition

• The indicator lamp has burned out (chapter 12).
• Open, disconnected or loose contact in the indicator lamp circuit (chapter 12).
• Generator failure (chapter 5A).

The lighting fixtures are not working

• The lamp burned out (chapter 12).
• Corrosion of the contacts of the bulb or socket (chapter 12).
• The fuse has blown (chapter 12).
• Relay failure (chapter 12).
• Break, disconnection or loose contact in the circuit (chapter 12).
• The switch is faulty (chapter 12).

Inaccuracy or instability of instrument readings

Instrument readings increase with increasing engine speed

• Generator or voltage regulator failure (chapter 5A).

Fuel or temperature gauges do not show any readings

• Malfunction of the pointer sensor (chapters 3 and 4).
• The wiring circuit is open (chapter 12).
• Pointer malfunction (chapter 12).

Fuel or temperature gauges constantly show maximum readings

• Malfunction of the pointer sensor (chapters 3 and 4).
• Short circuit in electrical wiring (chapter 12)
• Pointer malfunction (chapter 12).

Failure or poor performance of the horn

The sound signal does not turn off

• Short to ground or stuck horn button (chapter 12).
• Short circuit to ground of button wire (chapter 12)

The sound signal does not work

• The fuse has blown (chapter 12).
• A broken, loose or disconnected wire or wire connections (chapter 12)
• Sound signal malfunction (chapter 12).

Pulsation or intermittent sound from the horn

• Loose wire connections (chapter 12)
• Loosening of the horn mount (chapter 12).
• Sound signal malfunction (chapter 12).

Windscreen wipers fail or do not operate satisfactorily

Windscreen wipers do not work or work very slowly

• Wiper blades sticking to the glass or the linkage jamming (chapters 1 and 12).
• The fuse has blown (chapter 12).
• A broken, loose or disconnected wire or wire connections (chapter 12).
• Windscreen wiper motor malfunction (chapter 12)

The wiper blades are moving over too large or too small an area of the glass

• Incorrect installation of windshield wiper arms on shafts (chapter 1).
• Excessive wear of the wiper linkage (chapter 12).
• Loose windshield wiper motor or linkage (chapter 12).

Windscreen wipers are not working effectively

• Wear or damage to the rubber wiper blades ("Weekly checks").
• Breakage of the pressure springs or jamming of the swing arm hinges (chapter 12).
• Insufficient content of cleaning additive in the washer fluid for effective cleaning of the glass ("Weekly checks").

Washer failure or poor performance

One or more washer nozzles are not working

• Contamination of injector holes (chapter 1).
• Disconnection or kinking of the hose (chapter 12).
• Not enough fluid in the washer reservoir ("Weekly check").

The washer pump does not work

• The electrical wiring is broken (chapter 12).
• The fuse has blown (chapter 12).
• Washer switch malfunction (chapter 12).
• Washer pump malfunction (chapter 12).

Time delay between the start of the washer pump operation and the start of spraying liquid from the nozzles

• Malfunction of the check valve in the washer hose (chapter 12).

Electric window failure or poor performance

The glass moves in one direction only

• Switch malfunction (chapter 12).

The glass moves slowly

• Damage, sticking or lack of lubrication of the window lift drive (chapter 11).
• Contamination of the drive or internal components of the door (chapter 11).
• Electric motor failure (chapter 11).

The glass does not move

• The fuse has blown (chapter 12).
• Relay failure (chapter 12).
• Electrical wiring fault (chapter 12).
• Electric motor failure (chapter 12).

Failure or poor performance of the central locking system

The system is completely inoperative

• The fuse has blown (chapter 12).
• Control unit malfunction (chapter 11).
• Electrical wiring fault (chapter 12).
• Electric motor failure (chapter 11).

Locks close but do not open or open but do not close

• Main switch malfunction (chapter 12).
• Breakage or separation of the levers or rods of the lever transmission of locks (chapter 11).
• Control unit malfunction (chapter 12).
• Electric motor failure (chapter 11).

The electromagnet/electric motor of one of the locks does not work

• Electrical wiring fault (chapter 12).
• Malfunction of the actuator (chapter 11).
• Breakage or separation of the levers or rods of the lever transmission of locks (chapter 11).
• Door lock malfunction (chapter 11).