2001 Chevy Silverado battery light goes on then goes off

I have a chevy silverado 2001 model,when driving the battery light goes on for about 25 seconds then goes off. I had already replaced the battery,alternator,and drive belt at 148,000 miles.I had also "cleaned" the battery terminals and made sure that all the connections were right.I had the alternator "tested"and the test came back normal,this doesn't happen all the time just every once in a while,when Im driving. If anyone can help me with this I would be very thankful.

yours respectfully, Jason