Battery light comes on intermittent when just cruising. Light comes off after about a minute or so. I put a ground wire from alternator to negative battery post. Battery light still comes on but only under heavy load. I put a ground cable from engine to frame and ground wire direct from alternator directly to battery. Any other suggestions.

 

Find a competent shop and get your alternator tested, it probably has an open diode.

 

Does the alternator need to be removed in order to get tested or can the test be performed on the car?

 

They can be tested on the vehicle with the correct tester. We use them at work with our fleet of trucks.