Volkswagen Repair: 1990 Jetta starting problems, cold mornings, battery problem

Question
I have a 1990 Volks, Jetta Carat, automatic trans. At first we thought the problem was the starter but replaced it and the battery. Problem is that after the car has been driven for about a half an hour it will not start again for an average of an hour. also sometimes when it doesn't start a jump will get it going but the past two times it just wanted to rest and when i started it the next morning it did with no problem. Sometimes on cold mornings the battery sounds like it is hesitating and the battery light will be on for about half a minute. thanks for your time.

Answer
Check the charging system.  Something is not right here as it sounds as though it is draining the batttery.  Your fan belt should be tight, make sure that it is, but I believe that a diode is burnt out.  Go to an auto electric shop(a place where starters, altenators are fixed and have them look.  LOL