1982 240D 236K+ mi. Noticed the other day that the power windows were not going up and down as fast as they used to but didnt think anything of it. This morning on the way to work I noticed the batt light was dimly lit. When I got to work I checked the alt belt and found it was a little loose so I tightened it up at lunch time. When I got home from work I checked the charging volts and found it was only at 12V and also the batt light was not comming on when the ignition switch was turned on. Went to the local auto electric shop and purchased a new regulator for $28 CDN. After installation, the problem was resolved and charging volts were up to 13.6V and the batt light was comming on when the ignition switch was turned on and going off once the car was started. Tips from this forum led me to suspecting the regulator.
Thanks for all your posts.
Tom