There is a fan blade in front of the radiator that I have been told does not work. Might this be the problem, or part of the problem? What do you mean by the fan drawing system voltage down below operating threshold? You have outlined several "connections." If one of those is not clean, or loose, could that be the problem? Is there any chance the computer in the car is bad?
I appreciate the hlep you've given me so far, and these are my last questions. I believe I switched the main rely with the one in my daughter's car some time ago. She has a 1990 BMW 325i. I didn't notice any difference then. If this is a connection problem, then what explains that I cannot start the car right after it stops. And why will it start later in the day, or the next day, if it won't start up again right after it stops? Thank you.