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Alternator
This photo shows the same type of part you'll receive. Since each used part has its own wear and scratches, yours may look slightly different. Check the product notes for details about the condition of this specific part.

2003 - 2009 Chevrolet Trailblazer Alternator (OEM)

✓ IN STOCK
$59.95

ℹ️ Product Notes

This is a used part. It is an Alternator assembly. This part fits vehicles with the 4.2L, 6-cylinder engine.

Fits 4.2L 6-cylinder engines only. Check your engine size on the door sticker or under the hood before buying.
Condition: Excellent (A)
Like new, minimal to no wear
94,079 miles
Odometer reading when part was removed
See Other Chevrolet Trailblazer Alternators
SKU #
3821321-17100-106

Why Buy Used OEM Parts?

✓ Quality-Verified: Every used OEM part we sell has been professionally inspected and tested to ensure it meets our quality standards. While it may show some cosmetic wear from previous use, it's fully functional and ready to install.

✓ Original Equipment: This is a genuine OEM (Original Equipment Manufacturer) part - the exact same part that came with your vehicle from the factory. It's designed specifically for your make and model, ensuring perfect fitment and performance.

✓ Works Like New: Despite some visual wear, this part will perform just as well as a brand new one. The internal components and functionality are intact, giving you the same reliability you'd expect from OEM quality.

✓ Significant Savings: Save 50-80% compared to buying new! Used OEM parts offer exceptional value - you get factory quality at a fraction of the cost. It's the smart choice for budget-conscious vehicle owners who won't compromise on quality.

✓ Risk-Free Purchase: We stand behind our used parts with a generous 6-month warranty, 30-day returns, and 100% money-back guarantee. If it doesn't work out for any reason, simply return it for a full refund. You have nothing to lose!

🛡️ 30-Day Returns + 6-Month Warranty - Buy with Confidence!

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Vehicle Fitment Guide

This part fits the following vehicles:

Chevrolet
Trailblazer 2003-2009 (tapclick to expand)(tapclick to hide)
Swipe left/right to see more info
SubmodelSUB-
MODEL		 Body Style Years Engine Attributes
Base SUV 2003 - 2008 L6 4.2L RWD | Automatic | Fits 4.2L 6-cylinder engine only
LS SUV 2003 - 2007 L6 4.2L RWD/4WD | Automatic | Fits 4.2L 6-cylinder engine only
LT SUV 2003 - 2009 L6 4.2L RWD/4WD | Automatic | Fits 4.2L 6-cylinder engine only
LTZ SUV 2003 L6 4.2L RWD/4WD | Automatic | Fits 4.2L 6-cylinder engine only
North Face SUV 2003 - 2004 L6 4.2L RWD/4WD | Automatic | Fits 4.2L 6-cylinder engine only
A SUV 2004 - 2007 L6 4.2L RWD | Automatic | Fits 4.2L 6-cylinder engine only
B SUV 2004 - 2007 L6 4.2L RWD | Automatic | Fits 4.2L 6-cylinder engine only
Q SUV 2005 L6 4.2L RWD | Automatic | Fits 4.2L 6-cylinder engine only
R SUV 2005 L6 4.2L RWD | Automatic | Fits 4.2L 6-cylinder engine only
B SUV 2006 L6 4.2L 4WD | Automatic | Fits 4.2L 6-cylinder engine only
Base SUV 2008 L6 4.2L 4WD | Automatic | Fits 4.2L 6-cylinder engine only

⚠️ Important: Please verify your vehicle's year, make, model, and specifications before ordering. If you're unsure about fitment, contact our customer service team for assistance.

Policies

Shipping & Handling

  • Standard shipping: 3-7 business days via UPS Ground
  • Parts are carefully packaged to prevent damage during transit

Returns (30 Days)

We accept returns within 30 days of delivery for this part.

  • Defective parts: We will replace the part or issue a refund at our discretion
  • Electronic parts: Must be returned with the sealed inspection bag unopened. The clear bag allows full visual inspection before opening. Once opened, electronic parts can only be exchanged for a replacement if defective — no refunds
  • Programming: "Needs to be programmed to my vehicle" is not a valid return reason. Many modules require dealer programming — we're happy to help connect you with resources if your dealer says it's not programmable
  • Return shipping: We cover return shipping as part of our 100% money-back guarantee
  • Parts must be returned in original packaging and unmodified condition
  • Poorly packaged returns that arrive damaged will not be credited

6-Month Warranty

All used parts include a 6-month warranty from the date of purchase.

  • If your part fails within 6 months, we will send a replacement
  • Refunds are only issued if we cannot provide a suitable replacement
  • Warranty covers defects — not installation errors, misuse, or damage after installation

Note: Warranty is for replacement, not refund. A part failing on day 80? We'll replace it. But the return window for refunds is 30 days.

Damaged in Shipping?

If your part arrives damaged:

  • Stop immediately — do not install the part
  • Keep all original packaging and boxes
  • Take clear photos of the damage and packaging
  • Contact us within 48 hours of delivery

We will handle the carrier claim. You are not responsible for shipping damage — we just need your help documenting it.

Order Cancellation

Orders can be cancelled before shipment for a full refund. Once shipped, cancellations follow our return policy.

Symptoms & Diagnosis

Warning Signs Your Alternator is Failing

  • Dim or flickering headlights, especially at low speeds.
  • The battery warning light stays on even after starting the engine.
  • The engine stalls frequently, especially when using electrical accessories.
  • Slow or no-start condition.
  • Whining or growling noises coming from the alternator.
  • Electrical accessories like power windows or seats operate slowly.

How to Test if This Part is the Problem

  1. Check the Battery: A weak battery can mimic alternator problems. Make sure your battery is fully charged and in good condition before testing the alternator.
  2. Visual Inspection: Look for obvious signs of damage to the alternator, such as cracked housing, loose wires, or a burnt smell.
  3. Voltage Test: Use a multimeter to measure the voltage at the battery terminals while the engine is running. A healthy alternator should produce around 13.5 to 14.5 volts. If the voltage is significantly lower, the alternator may be failing.
  4. Load Test: Have a professional perform a load test on the alternator to see how it performs under stress. This test will determine if the alternator can provide enough power to meet the vehicle's electrical demands.

Common Failure Causes

  • Worn Brushes: The brushes inside the alternator wear down over time, reducing its ability to generate electricity.
  • Bad Bearings: Worn bearings can cause the alternator to make noise and eventually fail.
  • Faulty Voltage Regulator: The voltage regulator controls the amount of voltage produced by the alternator. If it fails, the alternator may overcharge or undercharge the battery.
  • Damaged Diodes: Diodes convert AC voltage to DC voltage. If they fail, the alternator will not produce enough power.
  • Overheating: Excessive heat can damage the alternator's internal components.

Buyer's Checklist

What to Look for When Buying This Part

  • Correct Fit: Ensure the part is designed for your specific vehicle year and model.
  • Reputable Source: Purchase from a trusted supplier with a good reputation.
  • Warranty: Look for a part with a warranty to protect against defects.
  • Condition: Carefully inspect the part for any signs of damage or wear.

Quality Indicators

FeatureUsed OEMRefurbished OEMNew Aftermarket
OriginOriginal factory partOriginal factory partThird-party manufacturer
TestingTested and inspectedTested and restoredMeets OE specifications
ComponentsOriginal components (may show wear)Some new components, some originalAll new components
PriceTypically lowestMid-rangeMid-range to premium

What's Typically Included

  • The alternator unit itself.
  • Mounting hardware may or may not be included. Check with the seller.

Installation Overview

Difficulty Level and Estimated Time

  • Difficulty: Intermediate
  • Estimated Time: 1-3 hours

Special Tools Needed

  • Socket set
  • Wrench set
  • Screwdrivers
  • Multimeter (optional, for testing)
  • Belt tensioner tool (may be required)

Critical Steps and Tips

  1. Disconnect the Battery: Always disconnect the negative battery cable before working on the electrical system.
  2. Remove the Serpentine Belt: Use a belt tensioner tool to relieve tension on the serpentine belt and remove it from the alternator pulley.
  3. Disconnect Electrical Connections: Carefully disconnect the electrical connectors from the alternator.
  4. Remove Mounting Bolts: Remove the bolts that secure the alternator to the engine.
  5. Install the New Alternator: Install the new alternator in the reverse order of removal.
  6. Reconnect the Battery: Reconnect the negative battery cable.

DIY or Professional Installation?

  • DIY is possible for mechanically inclined individuals. However, professional installation is recommended if you are not comfortable working on your vehicle's electrical system. A professional can ensure proper installation and diagnose any related issues.

Buying Options

Compare: Used OEM, Refurbished OEM, New Aftermarket

Choosing the right alternator depends on your budget and needs. Here's a comparison of your options:

Used OEM

  • Description: Genuine factory parts that have been removed from used vehicles.
  • Pros: Best value, genuine factory quality, tested and inspected.
  • Cons: May have some wear and tear.

Refurbished OEM

  • Description: Factory parts that have been professionally restored with new components.
  • Pros: Restored to like-new condition, reliable performance.
  • Cons: Slightly more expensive than used OEM.

New Aftermarket

  • Description: Brand new third-party parts built to OE specifications.
  • Pros: All new components, often more affordable than new OEM (which we don't sell).
  • Cons: Quality can vary depending on the manufacturer.

Typical Lifespan

How Long This Part Normally Lasts

  • An alternator typically lasts between 5 to 10 years, or 80,000 to 150,000 miles.

Factors That Affect Longevity

  • Driving Conditions: Frequent short trips, extreme temperatures, and rough roads can shorten the alternator's lifespan.
  • Electrical Load: Using a lot of electrical accessories, such as air conditioning, headlights, and a powerful sound system, can put extra strain on the alternator.
  • Maintenance: Regular maintenance, such as checking the battery and serpentine belt, can help extend the alternator's lifespan.

Price Ranges

Budget vs Mid-Range vs Premium Options

  • Used OEM: $50 - $150
  • Refurbished OEM: $100 - $250
  • New Aftermarket: $150 - $350

Labor Cost Considerations

  • Labor costs for alternator replacement typically range from $100 to $300, depending on the shop and the complexity of the job.

Total Job Cost Estimates

  • Used OEM: $150 - $450
  • Refurbished OEM: $200 - $550
  • New Aftermarket: $250 - $650

Vehicle-Specific Notes

Known Issues

  • Some models within this vehicle range have had reports of voltage regulator failures, leading to overcharging or undercharging of the battery.
  • Check for any Technical Service Bulletins (TSBs) related to the charging system for your specific year and model.

Verification After Install

How to Confirm Proper Operation

  1. Check the Battery Warning Light: The battery warning light should turn off after starting the engine.
  2. Voltage Test: Use a multimeter to measure the voltage at the battery terminals while the engine is running. It should be between 13.5 and 14.5 volts.
  3. Load Test: Turn on several electrical accessories, such as headlights, air conditioning, and the radio. The voltage should remain stable.

What to Look/Listen for

  • No unusual noises coming from the alternator.
  • Stable voltage readings with electrical accessories on.
  • No dimming or flickering headlights.

FAQ

Q: How do I know if my alternator is bad or if it's just my battery?
A: A simple test is to jump-start your car. If it runs fine after the jump, but dies shortly after disconnecting the jumper cables, it's likely the alternator. If it still doesn't start, the battery may be the problem.

Q: Can I drive with a bad alternator?
A: It's not recommended. A bad alternator can cause your car to stall unexpectedly and leave you stranded. It can also damage other electrical components.

Q: How long does it take to replace an alternator?
A: Typically, it takes between 1 to 3 hours to replace an alternator, depending on the vehicle and the mechanic's experience.

Q: What does "OEM" mean?
A: OEM stands for Original Equipment Manufacturer. It means the part was originally made by the same manufacturer that made the part for your car when it was new.

Q: Will a new alternator fix my battery problems?
A: If your battery problems are caused by a faulty alternator that isn't charging the battery properly, then yes, replacing the alternator should fix the issue. However, if your battery is old or damaged, you may also need to replace the battery.

Part Specifications

OEM Part Numbers:

  • GM: 15062413, 15093928, 15117974, 15117975, 15200109, 15225928
  • Isuzu: 8152259280
  • Saab: 15-22-5928

Fits Years: 2002 2003 2004 2005 2006 2007 2008 2009

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