BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
- 13. Electric equipment
   13.1.2. Search of malfunctions
   13.1.3. Safety locks
   13.1.4. Relay
   13.1.5. Breaker of indexes of turn/alarm system
   13.1.6. Switches on a steering column
   13.1.7. Ignition lock
   13.1.8. Receiver
   13.1.9. Antenna
   13.1.10. Guard of devices
   13.1.11. Payment SI (index of maintenance)
   13.1.12. Headlights – replacement of lamps
   13.1.13. Adjustment of headlights
   13.1.14. Headlight case
   13.1.15. Replacement of lamps
   13.1.16. Screen wiper electric motor
   13.1.17. Heater of back glass
   13.1.18. Safety cushions
   13.1.19. System cruise control
   13.1.20. The central locking system
   13.1.21. Electric stelokpodjemnik
   + 13.2. Electrical circuitries
+ 14. Useful tips


13.1.2. Search of malfunctions


The consumer, switches, relay and wires connected according to the enclosed scheme are a part of electric chains of the car. Before starting troubleshooting it is necessary to study the scheme and to define a possible source of malfunction. For example, problem of troubleshooting is considerably facilitated if it is possible to check serviceability of other consumers directly or indirectly connected to the suspected chain.

If the refusal of several consumers is observed, then the break of connection with weight or burn-out of a safety lock is the most probable cause. As a rule failures of electric equipment are caused by weakening of contacts or their corrosion, burn-out of a safety lock or an oplavleniye of a crossing point. Search of malfunctions as a rule is carried out by means of a tester (voltmeter) or a control lamp which are connected between the site of a faulty chain and well smoothed out site of weight.

For check of reliability of connection with weight connect through an ohmmeter (or through a control lamp to the battery) checked connection of a wire with weight and well smoothed out site of weight. If the ohmmeter shows a chain (or the lamp will light up), then connection with weight reliable. Otherwise the contact with weight is broken. Keep in mind that in most cases weight serves as the return current distributor connecting a chain to a negative pole of the battery. Therefore violation of connection with weight, or a gap in a chain of the return current on the battery, can be the main reason for refusal.


Part of cars is equipped with safety cushions (so-called SRS system of additional safety). Works on repair of electric equipment in salon on these cars should be performed only in car service.