Audi 80 Quiz
Body Electrical System

Fault Finding - Battery and Alternator

In this manual: Body Electrical System
Technical Description — 39Engines — 41Exhaust System — 13Cooling System — 28Fuel tank and fuel pump — 12Air Filter and Intake Ducts — 13Mono-Motronic Injection System — 18Digifant Injection System — 19KE-III-Jetronic Injection System — 35MPI and MPFI Injection Systems — 32Clutch — 11Transmission and Driveline — 21Suspension and Steering — 33Brake System — 41Anti-lock brake system — 8Wheels and Tires — 13Body Electrical System — 35Ignition System — 24Lighting — 14Signaling Devices — 7Instruments and Auxiliary Equipment — 54Heating and Ventilation — 7Body Components — 18Troubleshooting — 6Specifications — 13
~1min read

Malfunction Possible Cause Remedy
A. Battery charge indicator lamp does not light when the ignition is switched on 1. Discharged battery
2. Battery cable damaged, terminals loose or corroded
3. Faulty bulb
4. Wiring interrupted between ignition switch, charge indicator and alternator
5. Earth lead between alternator and engine block damaged
6. Worn brushes
7. Faulty voltage regulator
8. Alternator damaged
9. After washing the engine, moisture has entered and formed an insulating oil film between the slip rings and alternator brushes		 Start the engine using jumper cables from another battery or by towing
Check the battery cable and terminals
Replace
Check the wiring to the warning lamp
Check the lead
Replace the regulator
Replace the regulator
Have the alternator repaired (in a workshop)
Blow the alternator out with compressed air or wipe the slip rings and brushes clean
B. Battery charge indicator lamp lights or glows with the engine running 1. V-belt or poly-V belt loose or damaged
2. Poor contact at wire connections or broken wire
3. See A 6 – 8		 Tension or replace the belt, or check the belt tensioner
Check the wire connections and the wires themselves
C. Battery surface is wet 1. Battery overfilled
2. Battery cap blocked
3. See A 7		 Excess distilled water: bring it to a gaseous state by overcharging and let it escape. Do not siphon off the electrolyte
Clean the vent openings
D. Battery is "boiling" See A7

Test yourself

A quick Audi 80 quiz: every answer comes with an explanation and a link to the manual page.