Generator fault diagnostics (VAZ-21061)

Cause of malfunction	Method of elimination
Battery charge indicator lights up when engine is running
The alternator belt is loose or broken	Tighten your belt
Generator excitation circuit faulty (it produces the required voltage only at high speeds with a small output current), the voltage regulator is damaged (to check, use two DC sources with voltage of 12 and 15 V (see Electrical equipment) or replace the regulator with a known good one)	Clean oxidized contacts, crimp terminals, replace blown fuse #10, faulty voltage regulator
Brushes are stuck or worn out, contact rings are oxidized (the generator produces the required voltage only at high speeds with a small output current). The protrusion of the brushes from the brush holder must be at least 5 mm	Clean the contact rings with fine glass sandpaper, check for beating. Eliminate brush sticking, replace the brush holder if they are worn out
Unsoldering of excitation winding leads from slip rings, short circuit or open circuit in winding	Solder the leads or replace the generator rotor or generator assembly
Open or short circuit in the stator winding, short circuit to ground (when shorted, the generator "howls")	Check the winding with an ohmmeter. Replace the stator or the generator assembly
Short circuit of one or more positive valves	Replace the radiator with positive valves
Break in one or more valves	Replace the radiator with positive valves, re-press the negative valves or replace the rear generator cover
Open circuit between the generator plug "85" and the star center of the stator windings (checked with an ohmmeter)	Restore connection
The charge indicator relay is faulty (see Electrical equipment)	Replace the relay
The charge indicator does not light up, but the battery charges poorly (the engine turns over with difficulty when starting). The voltage in the on-board network is below 13.6 V (checked by autotester)
The alternator belt is not tensioned properly	Tighten your belt
Too many powerful power consumers are switched on, especially at low engine speeds. Short circuit in consumers (usually these are windings of electric motors)	Limit the use of powerful consumers at idle, do not connect additional consumers in excess of the generator's permissible power, check the windings of electric motors for short circuits
Generator excitation circuit and voltage regulator are faulty	Clean oxidized contacts, crimp terminals, replace faulty voltage regulator
Brushes are stuck or worn out, contact rings are oxidized (the generator produces the required voltage only at high speeds with a small output current). The protrusion of the brushes from the brush holder must be at least 5 mm	Clean the contact rings with glass cloth, check for beating. Eliminate brush sticking, replace the brush holder if they are worn out
Unsoldering of excitation winding leads from slip rings, short circuit or open circuit in winding	Solder the leads or replace the generator rotor or generator assembly
The fastening has become loose or the wire tips on the "+" terminal of the generator, battery, or terminals in the splitter have become oxidized (on the right mudguard in the engine compartment)	Clean terminals and tips, tighten connections
Open or short circuit in the stator winding, short circuit to ground (when shorted, the generator "howls")	Check the winding with an ohmmeter. Replace the stator or the generator assembly
The rectifier block diodes are damaged	Replace diodes or rectifier block
The battery is recharging (electrolyte levels drop rapidly). The voltage in the vehicle's on-board network is higher than 14.7 V (checked by autotester)
The voltage regulator is faulty	Replace the regulator
Short circuit between the brush holder mounting screw and the brush bus connected to the controller pin "W" (G-221)	Repair the short circuit or replace the plastic base of the brush holder
Battery charge indicator does not light when ignition is turned on
The light bulb burned out	Replace the lamp
The contacts of the lamp holder have come loose or oxidized	Clean and crimp the contacts
The charge indicator relay is faulty (see Electrical equipment)	Replace the relay
Short circuit in one or more negative valves	Re-press the negative valves or replace the generator rear cover
Short circuit of stator winding to ground (generator "howls") Open circuit between plug "87" of the charge indicator and the fuse box	Check the winding with an ohmmeter. Replace the stator or the generator assembly Restore connection
Generator noise
The generator bearings are damaged (squealing, howling), the seat in the generator cover is worn out. (The noise remains when the wires are disconnected from the generator, but disappears if the belt is removed)	Replace bearings, cover or alternator assembly
The rotor touches the stator poles	Check the rotor shaft runout, bearings and mountings for wear. Replace defective parts or the generator assembly
Short circuit in the stator winding, its short circuit to "ground" (the generator "howls"). The noise disappears if you disconnect the wires from the generator	Replace the stator or generator assembly
Short circuit in one of the main valves. Noise disappears if you disconnect the wires from the generator	Replace the radiator with positive valves, re-press the negative valves or replace the rear generator cover