Hi, The battery charge light on our '85 Golf (1.8 L gas engine) came on this afternoon and stayed on.
Tonight I did some checking. The battery was low on liquid and topping up the 6 cells took a total of about 250 ml of water (about a cup).
I started the engine and the light stayed on. Revving the engine usually kills the light but not this time. Light stayed on
Next I checked the alternator output and there is 14.3 V across the battery terminals. Bently suggests between 13.5 and 14.5 V is normal so at 14.3 V the voltage regulator seems to be okay.
Posts in the archives of rec.autos.makers.vw.watercoold suggested checking voltage along the circuit starting at the D+ terminal on the alternator to the charge indicator light and back to the POS battery terminal. Results using a digital multimeter:
Voltage from D+ terminal to ground = 11.68 V Voltage from battery + terminal to ground = 14.43 V
Is it normal for the D+ terminal to be putting out such a low voltage relative to the charging current?
Any suggestons on what to check next? The alternator, an after-market one from Canadian Tire (auto parts store), is about 8-1/2 years old with 80,000 km on it (50,000 miles).
Is it okay to run the car until I figure out what the problem is--any damage I might do?
thanks very much,
-Tony
-------------------- twong(at)vcn.bc.ca Vancouver, BC Canada