Cause of malfunction | Elimination Method |
The battery warning light comes on when the engine is running | |
Loose or broken alternator belt | Pull up the belt |
Faulty generator excitation circuit (it produces the prescribed voltage only at high speeds with a small recoil current), damaged voltage regulator (use two 12 and 15 V DC sources for testing (see electrical equipment) or substitute a known-good regulator) | Strip oxidized contacts, crimp terminals, replace blown #10 fuse, faulty voltage regulator |
Brushes hung or worn, slip rings oxidized (the generator produces the required voltage only at high speeds with a small recoil 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 runout. Eliminate the sticking of the brushes, if they are worn, replace the brush holder |
Desoldering the excitation winding leads from slip rings, short circuit or open circuit in the winding | Solder leads or replace alternator rotor or alternator assembly |
An open or short circuit in the stator winding, shorting it to «mass» (when the generator is closed «howls») | Check the winding with an ohmmeter. Replace stator or generator assembly |
Short circuit of one or more positive valves | Replace radiator with positive valves |
Break in one or more valves | Replace radiator with positive valves, repressurize negative valves or replace alternator rear cover |
Break between plug «85» generator and star center of stator windings (checked with an ohmmeter) | Restore connection |
Faulty charge indicator relay (see electrical equipment) | Replace relay |
The charge indicator does not light up, but the battery is not charging well (Difficulty cranking the engine when starting). The voltage in the on-board network is below 13.6 V (checked by autotester) | |
Poorly tensioned alternator belt | Pull up the belt |
Too many powerful electrical consumers are switched on, especially at low engine speeds. Short circuit in consumers (usually these are motor windings) | Limit the use of large consumers at idle, do not connect additional consumers in excess of the allowable power of the generator, check the motor windings for short circuits |
Faulty generator excitation circuit, voltage regulator | Strip the oxidized contacts, crimp the terminals, replace the faulty voltage regulator |
Brushes hung or worn, slip rings oxidized (the generator produces the required voltage only at high speeds with a small recoil current). The protrusion of the brushes from the brush holder must be at least 5 mm | Clean the slip rings with glass paper, check for runout. Eliminate the sticking of the brushes, if they are worn, replace the brush holder |
Desoldering the excitation winding leads from slip rings, short circuit or open circuit in the winding | Solder leads or replace alternator rotor or alternator assembly |
Loose fastening or oxidized wire lugs on the output «+» generator, battery, terminals in the splitter (on the right mudguard in the engine compartment) | Strip the terminals and lugs, tighten the connections |
An open or short circuit in the stator winding, shorting it to «mass» (when the generator is closed «howls») | Check the winding with an ohmmeter. Replace stator or generator assembly |
Damaged rectifier diodes | Replace diodes or rectifier unit |
The battery is being recharged (electrolyte levels drop rapidly). The voltage in the vehicle's on-board network is higher than 14.7 V (checked by autotester) | |
Faulty voltage regulator | Replace Regulator |
Short circuit between the screw of the brush holder and the brush bus attached to the output «W» regulator (G-221) | Repair the short or replace the plastic base of the brush holder |
The battery charge indicator does not light up when the ignition is turned on | |
Bulb burnt out | Replace lamp |
Loose or oxidized lamp holder contacts | Clean, crimp contacts |
Faulty charge indicator relay (see electrical equipment) | Replace relay |
Short circuit in one or more negative valves | Repress negative valves or replace alternator rear cover |
Short circuit of the stator winding «mass» (generator «howls») | Check the winding with an ohmmeter. Replace stator or generator assembly |
Generator noise | |
Damaged alternator bearings (squeal, howl), wear of the seat in the generator cover. (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 runout of the rotor shaft, wear of bearings and seats. Replace defective parts or alternator assembly |
Short circuit in the stator winding, shorting it to «mass» (generator «howls»). The noise disappears if you disconnect the wires from the generator | Replace stator or generator assembly |
Short circuit in one of the main valves. The noise disappears if you disconnect the wires from the generator | Replace radiator with positive valves, repressurize negative valves or replace alternator rear cover |