I got this 2004 S60 2.4 a month ago and they said it needed a new alternator.....battery would go flat.
I checked the alternator output and it was 13.8 sometimes! A little research suggested that the voltage regulator on the end of the alternator was probably the problem, so I changed it, and this seemed to fix the problem. Then yesterday, the Low Battery light came on again, and on the way home, EVERYTHING was acting up.....dim then bright headlights, auto transmission jumping in and out of gear etc
At home the battery showed 3.5volts. After charging all night, it only showed 11,7 volts, so I put in another good battery that went in with 12.6 but quickly showed 11.8??
After starting, it still showed 11.7 when the motor was running. So I drove it about 5 miles, and it was still at only 11.6 volts.
I charged it then drove it again, and now the alternator seems to be working fine again showing 14,2 with the motor running..
I just drove again and the alternator is still working, so it looks to be OK, but I don't trust it.
When It stopped working, I charged the battery up, and maybe this charging seems to be doing something good? Maybe?
Does anyone have any thoughts why the alternator would work then not work, then work.