Buick 1993 Roadmaster Owner's Manual page 120

' d .
, .
dhen you turn the key to "Run," this light will coine on
briefly, to show that your alternator and battery charging
systems are working. If a light-stays on, you need
service, and you should take your Buick to the dealer at
once. To save your battery until you get there, turn off
all accessories, and set your air system to
'"OFF."