How to Replace Alternator 96-99 GMC Sierra K1500 5.7L

Difficulty: Intermediate · About 40 min · Gmc Sierra K1500

Replace the alternator on a 1996-1999 GMC Sierra K1500 with the 5.7L engine.

Steps

1. Disconnect the battery

   Disconnect the negative terminal with an 8mm wrench.

2. Release the serpentine belt

   Note the routing, fit a 3/8 inch drive ratchet into the tensioner, turn it clockwise to slacken the belt, then slip it off the alternator and pull it free.

3. Remove the old alternator

   Remove its rear 10mm bolt and two bottom 13mm bolts, wiggle it loose with a pry bar, unplug the wiring harness, then lift the rubber boot and remove the remaining 13mm bolt before taking it out.

4. Install the new alternator

   Set the power terminal, lock washer and 13mm nut on first with the boot folded back, reconnect the wiring harness, press the alternator into place, then tighten its 13mm and 10mm mounting bolts.

5. Reinstall the serpentine belt

   Loop it around the crank, water pump, power steering, A/C, tensioner and idler pulleys per the diagram, then use the 3/8 inch ratchet on the tensioner to pull it over the alternator.

6. Reconnect the battery

   Reconnect the negative terminal.

Check your vehicle’s repair manual for exact specifications and fit.