My 300e starts up fine but after like 15 to 20 minutes of driving the lights begin to fade out and the engine dies. After than it wont start up unless you wait for like a hour later. I have a new battery so im guessing its the alternator. Is it hard to replace the alternator as a diy job? Anyone have this similiar problem with thier 300e?

It definitely sounds like an alternator problem. Have someone test it. As far as replacing it yourself, it's pretty easy in these cars because there is a lot of space. Especially if you don't have the air pump (pre 89, I think).

Vinamg

Check out the brush assembly before you change the alternator. That is a 5 minute job to replace. There has been previous discussion about this so do a search for other details.