I have a 2007 C6 Coupe, 53,000 miles. I installed a new alternator (Upgrade) 240 Amp for new stereo, amp and other electronics. When I start cold it is fine. After about 20 minutes I get the Service Charging System when it is at idle. When I rev the motor or am driving it goes off. Shows 14- 14.5 volts at all times. When it returns to Idle service charging system returns. Sent the alternator back and received the new one but having the same problem. Battery is good too. Put the old alternator back on and no service charging system came on. Crazy!!!! Help anyone?

 

Welcome to the forum.

Not sure if this is the design in the Corvette but in the 2007 and up Tahoes, the computer controlled the alternator output. Perhaps your new alternator has a built-in regulator and it's not playing well with the computer regulation. Might check with the company that you got the new alternator from and see if they can answer that question.