Originally Posted by 8VETTE7

I would begin by checking out the battery and having it load tested. I would also measure the voltage at the battery with a meter at a time when the gauges show a low value to see what the meter reports. If the car has headers then I would definitely check the condition of the wires at the starter solenoid and check the tightness of the nut securing the cables to the solenoid. Also note the general condition of the cleanliness (lack of corrosion and burnt appearance) of those connections. The solenoid is the junction point of the alternator connections and the battery positive cable and many cars with headers have issues with this connection point due to the constant heat cycles......

If the above all check out next I would consider replacing the ignition switch. The gauges are down stream of the battery and carbon deposits on the ignition switch contacts can cause the voltage the gauges report to be greatly different than what is actually at the battery. Here is a link to check out the condition of the ignition switch:

diagnosis

http://forums.corvetteforum.com/1568186703-post64.html


Generally if the voltages at the fuses indicated in the link are more than about 0.3 volts less than at the battery the ignition switch is suspect and should be replaced. Bad ignition switch is a very common issue with the C5.


If this all comes back good and you are at a point of still having the symptoms, I would pull the alternator and have it tested. If the alternator is the issue then have YOURS rebuilt. DO NOT just throw any alternator in the C5 as the aftermarket alternatives almost always do not work correctly.

Here is a link to a sticky that you should read before replacing the alternator if you have not already done so:

https://www.corvetteforum.com/forums...nd-issues.html


Throwing parts at symptoms seldom produces the best results on C5 electrical issues. Knowing the cause of the symptoms is ALWAYS the best alternative. JMHO