24/7 Customer service
To make aftermarket auto parts an afterthought.
Add your vehicle
Address
Login
Cart
Item
CA$0.00
Add your vehicle to ensure fitment/Choose a yearRequired Fields
Select a different vehicle
Make/Model
VIN
Save

2005 GMC Sierra 1500 Alternator

8 items

Alternator replacement is the fix when batteries keep dying, lights fade, or charging warnings appear. Get a 12V car alternator ready for daily electrical load.

  • All filters
  • Sort By
  • Price
  • Brand
  • Warranty
2001-2003 2005 GMC Sierra 1500 HD Alternator 253A 12V Clockwise 6-Groove Pulley A-Premium APALT4272001-2003 2005 GMC Sierra 1500 HD Alternator 253A 12V Clockwise 6-Groove Pulley A-Premium APALT427
A-Premium®Part # APALT427
2001-2003 2005 GMC Sierra 1500 HD Alternator 253A 12V Clockwise 6-Groove Pulley A-Premium APALT427
4.717 Reviews
CA$216.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500 HD: 2001 2002 2003 2005
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
ConditionNew
item #1012TES7
Note
This item comes with 253A/12V, CW and 6 Grooves.
Show less
2001-2003 2005 GMC Sierra 1500 HD Alternator 105A 12V Clockwise 6-Groove Pulley A-Premium APALT549
A-Premium®Part # APALT549
2001-2003 2005 GMC Sierra 1500 HD Alternator 105A 12V Clockwise 6-Groove Pulley A-Premium APALT549
4.717 Reviews
CA$155.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500 HD: 2001 2002 2003 2005
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
ConditionNew
item #1003R25D
Note
This item comes with 4 pin plug, Not 2 pin.
Show less
2005-2007 GMC Sierra 1500 Alternator 150A 12V Clockwise 6-Groove Pulley A-Premium APALT046
A-Premium®Part # APALT046
2005-2007 GMC Sierra 1500 Alternator 150A 12V Clockwise 6-Groove Pulley A-Premium APALT046
4.717 Reviews
CA$221.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500: 2005 2006 2007
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
Part interchange
11075N, 11075, 0124525072, 0124525104, 10371020, 11075
ConditionNew
item #10137QU5
Show less
2001-2003 2005-2006 GMC Sierra 1500 HD Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT575
A-Premium®Part # APALT575
2001-2003 2005-2006 GMC Sierra 1500 HD Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT575
4.717 Reviews
CA$188.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500 HD: 2001 2002 2003 2005 2006
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
Part interchange
8292N, 8274, 113777, 10464476, 15226003, 15754097M, 19151921, 8104644760, 
...View more
ConditionNew
item #1003QZDU
Show less
2005-2007 GMC Sierra 1500 Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT428
A-Premium®Part # APALT428
2005-2007 GMC Sierra 1500 Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT428
4.717 Reviews
CA$182.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500: 2005 2006 2007
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
ConditionNew
item #1003QQ97
Note
This item comes with 145 Amp/12 Volt, Clockwise Rotation and 6-Groove Pulley.
Show less
1999-2005 GMC Sierra 1500 Alternator 105A 12V Clockwise 6-Groove Pulley A-Premium APALT549
A-Premium®Part # APALT549
1999-2005 GMC Sierra 1500 Alternator 105A 12V Clockwise 6-Groove Pulley A-Premium APALT549
4.717 Reviews
CA$155.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits GMC Sierra 1500: 1999 2000 2001 2002 2003 2004 2005
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
ConditionNew
item #1003R0XZ
Note
This item comes with 4 pin plug, Not 2 pin.
Show less
2005 GMC Sierra 1500 HD Alternator 150A 12V Clockwise 6-Groove Pulley A-Premium APALT046
A-Premium®Part # APALT046
2005 GMC Sierra 1500 HD Alternator 150A 12V Clockwise 6-Groove Pulley A-Premium APALT046
4.717 Reviews
CA$221.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2005 GMC Sierra 1500 HD
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
Part interchange
11075N, 11075, 0124525072, 0124525104, 10371020, 11075
ConditionNew
item #1016CU0R
Show less
2005 GMC Sierra 1500 HD Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT428
A-Premium®Part # APALT428
2005 GMC Sierra 1500 HD Alternator 145A 12V Clockwise 6-Groove Pulley A-Premium APALT428
4.717 Reviews
CA$182.99
Enter ZIP codeFree standard shipping
2-year warranty
90 days free return
Fits 2005 GMC Sierra 1500 HD
Add Trim and Engine info to ensure a guaranteed fit
Vehicle: 2005 GMC Sierra 1500
Item LocatedCanada
Quantity1
ConditionNew
item #10185C0V
Note
This item comes with 145 Amp/12 Volt, Clockwise Rotation and 6-Groove Pulley.
Show less

What does a car alternator do?

The alternator keeps your automobile alive when the engine is running, however, the battery is necessary to start your car when it is not functioning. The majority of your car's electronic parts, such as the headlights, electric steering, power windows, windshield wipers, heated seats, dashboard gauges, and radio, are powered by the alternator while you're moving or idle. All of them receive direct current (DC) electricity from the alternator. Your car's battery is also charged while you're driving thanks to your alternator.

By converting mechanical energy into electrical energy, the alternator operates. When your engine is running, it drives a drive belt that is suspended from an alternator pulley. A set of magnets is spun around a coil by the alternator's rotor shaft, which is turned by the pulley. Alternating current (AC) is produced by these rotating magnets and circulated through the coil to the rectifier of the alternator. Your car's electrical systems are turned on by the rectifier, which transforms that AC power into DC power.

How does a car alternator work?

A car alternator is a device that converts mechanical energy into electrical energy. It is responsible for charging the battery and powering the electrical systems of the car. When the engine is running, the alternator is driven by a belt connected to the engine's crankshaft. Inside the alternator, there is a stationary magnetic field and a rotating coil of wire called the rotor. As the rotor spins, it generates an alternating current (AC) by electromagnetic induction.

The output of the alternator is regulated by a voltage regulator, which maintains a constant voltage output even as the engine speed varies. When the battery is fully charged, the voltage regulator reduces the output of the alternator to prevent overcharging the battery. When the engine is idling, the alternator output may not be enough to power all of the car's electrical systems, so the battery may be used to provide additional power. When the engine is running at higher speeds, the alternator output increases to meet the demand for electrical power.

How a Replacement Alternator Supports Your Vehicle’s Electrical System

A replacement alternator converts mechanical energy from the engine into electrical energy to power the vehicle’s electrical system. It supplies electrical power to electrical components and electrical accessories while keeping the battery charged. In most charging system designs, the alternator works with a voltage regulator to maintain stable output and support direct current needs across the vehicle when the engine is running.

Bad Alternator Symptoms That Signal It’s Time to Replace

A bad alternator often shows clear symptoms: flickering headlights, dim lights, weak electrical power, and failing electrical accessories such as power windows. You may also see a dead battery even after driving, because the charging system can’t keep the battery charged. Other common causes that can look similar include a loose serpentine belt or poor connections—so it’s smart to test the alternator and belt before ordering a replacement.

How to Choose a Compatible Replacement Alternator and Order Fast

Select a replacement alternator by your vehicle’s year, model, and engine, then confirm compatible fitment and connector details. Use the page search to shop by top brands, check store stock, compare reviews and difficulty notes, and add the right unit to cart. For easier installation, verify the serpentine belt condition and access under the hood, and confirm all charging system components are in good shape before you change parts.

Related Blogs

Does an Alternator Charge a Battery at Idle?

Have you ever wondered if the alternator charges the battery at idle? If so, how much charge can you get? Or do you want to know how fast the battery charges at idle? How to measure it? This blog has the answers you need.

Aug 18, 2026

What Causes the Alternator to Go Bad

The alternator charges the battery, powers electrical components, and regulates voltage. By knowing its function and possible failures, you can take proactive measures to reduce the risk of encountering electrical system issues in your car.

Jul 21, 2026

Understanding Types of Car Alternators

Depending on their design, output power, cooling method, and alternators can be categorized in many ways. Different classification methods reflect the differences in performance, cost, reliability, etc. of alternators.

Jul 21, 2026

How to Replace a Car Alternator

Alternator is a vital component that converts engine energy into electricity, powering various systems in your vehicle. Although alternators are typically reliable, regular maintenance can prolong their lifespan and help prevent unexpected failures.

Jul 21, 2026