Randomly the alternator stops charging. The battery light comes on. I've taken the alternator to 2 different places and it checks out ok. You can turn the car off and on a couple of times and it starts working again. I've cleaned and tightened the connections on the Alternator and battery. Any suggestions.

 

Welcome to the forum...

Need to check your ground cable and the strap to the engine and body....
remember the ground wire closes the electrical loop...