It is on because the computer has detected a malfunction and set a trouble code. See related question below.
Where is the oil filter in a 2004 Chevy Malibu
How many motor mounts in 2004 Chevy Malibu?
it means your car needs a service
no
2004 Malibu has fuse box in the trunk. You will find the tail light fuse in there. 10 Amp fuse all the way to the rear, just under a much larger fuse.
the switch is on top back side of brake pedal.
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2004 chevy mailibu starter location
Wath timing 2.2 malibu 2004
Where is the power steering pump located for 2004 malibu
Yes. '97-'05 the same.
There is no user serviceable filter in 2004 to 2007 Chevy Malibu Maxx.