Parts for your Chevrolet Silverado 1500
2004 Chevrolet Silverado 1500 Alternators
Buy Chevrolet Silverado 1500 alternators online from 16 units for 1999-2018 trucks, priced from $82.98 to $341.98. Brands include Pure Energy, AC Delco, API, SKP, Powermaster and DIY Solutions. Fitment is listed by engine, covering the 4.3L V6 and the 4.8L, 5.3L and 6.0L V8, with case size notes where they apply.
Year
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Engine and output decide fitment
The alternator on a Silverado 1500 follows the engine and the factory charging option more than the cab, bed or trim. 1999-2006, 2007-2013 and 2014-2018 trucks each use their own applications, and a 2007 needs extra care because both older and newer designs appear that year.
On 1999-2002 trucks, output matters. Common units were 105 amp and 130 amp, and the 130 amp version tied to RPO code KG8 is not a match for every lower rated unit. Check the RPO sticker in the glove box. Some listings also note a 137mm case diameter. Compare amperage, plug shape, pulley grooves and mounting ears with the old unit.
Charging problems to watch for
A failing alternator often lights the battery or charging warning, lets the headlights dim or flicker, or slows down power windows and blower speed. You may get a dead battery after the truck sits, or a whine that rises with engine speed.
The usual internal causes are a failed voltage regulator, worn brushes or bearings, or bad diodes. A weak battery, loose ground, damaged charge cable or slipping belt can look exactly the same. Test the battery and charging voltage first so you replace the right part.
Swap tips and related checks
Disconnect the negative battery cable before you start. On 1999-2004 V8 trucks, the alternator sits high on the driver side. Release the serpentine belt tension, unplug the connectors and remove the mounting bolts.
While the belt is off, check it for cracks and spin the tensioner to feel for roughness. Clean the battery terminals and grounds. A new alternator will not fix a slipping belt or a corroded cable. After the swap, confirm the belt routing and measure charging voltage with lights and blower on.
More about alternators
Read our alternators buying guide for how the part works and what to look for in any vehicle.
Silverado 1500 questions
How do I know which amp alternator my Silverado 1500 needs?
Check the label on your old alternator and the RPO codes on the glove box sticker. On 1999-2002 trucks, code KG8 indicates the 130 amp unit. Match that rating in the fitment table.
Does 4WD or cab style change the Silverado 1500 alternator?
Usually not. Engine and charging option drive fitment. Drivetrain, cab and trim rarely change it, but factory equipment can. Pick your year and engine in the filter and read the listing notes.
Is my Silverado 1500 alternator bad or is it the battery?
Test both. A weak battery, poor ground or slipping belt can mimic a failing alternator. A parts store or meter check of battery health and charging voltage with the engine running will tell you which part is at fault.