Hello and welcome to the forum! I've attached 2 DIY tech articles from our site that I hope you find helpful in troubleshooting and addressing your charge issue. If you have any further questions, feel free to post a Comment just below the article and someone will get back to you with more detailed info. Best of luck!

Mercedes-Benz W123 Voltage Regulator Replacement | 300TD 1977-1985 | Pelican Parts DIY Maintenance Article

Mercedes-Benz W123 Alternator Replacement | 300TD 1977-1985 | Pelican Parts DIY Maintenance Article


-Dmitry