Over the past few weeks I have had problems with my Volvo not starting due to a flat battery. I made do with recharging the battery periodically, and yesterday finally got around to fixing it. I checked the alternator output, and found it to be only 13.2V. Following the trouble shooting in the Haynes manual, I found that the alternator was not working, so I went and bought a changeover alternator. I fitted this, started up the car, only to find that the alternator output is still only 13.2V (both at the battery and at the back of the alternator.) Other symptoms that I have noted are:

1) The battery warning light on the dash is illuminated with the key on, but the engine not running. When the engine is running, the light is not illuminated.

2) The alternator output drops from 13.2V to 12.4V when the headlights are turned on. This would seem to indicate that the voltage regulator was not working; however this was replaced with the alternator. (it is the integral kind, in the back of the alternator, Bosch).