2000 S-10 truck voltage shows 10 volts when temp is below 32 degrees and 14.9 volts above 32 degrees have replace battery (2014) and alternator is just 2 years old
Purchase a cheapie volt meter, nothing fancy, hook it directly to the battery and check voltage, it should read 12.9 to 13.2 volts, compare that to the dash gauge, if it reading lower then you either have a gauge or wiring problem. Now start the engine, voltage at the battery should be 13.9 to 14.2 compare that to the dash gauge, if it is reading higher or lower then again the gauge or wiring is at fault. Some of these gauges can be calibrated but only the dealer can tell you that, If this is a concern for you, an auxiliary volt meter can be installed.
The volt gauges on these are inaccutate. The idiot light for the battery will come on if the alternator fails with the engine running. If not like said above, check it yourself or have someone check it. If it's OK then just ignore the gauge
Search Chevrolet S-10 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet S-10 Experts