Voltage problem

Hello, have a big problem - for 2 days I only have approx. 11.5 volts on board voltage ?! After starting the car, the battery light, as well as the ABS (off) always lights up. I connected a voltmeter to the battery when running the engine -> 14V. The coals of the LIMA are OK, have also changed the cockpit crosswise, without success. I also checked the lines at LIMA. However, my high-automatics no longer work and the FH are very lame... What can that be? The day before, I had the same problem after the start, but that was fixed after the first gas burst. Ohso, vehicle is a 200 20V, but I think the problem might have the same causes with a V8 ?!? Thank you in advance
Welcome
Frank