Choosing the Right Alternator for Your 1979-1988 GMC G1500 Van
Keep your classic GMC van's electrical system reliable with the right new aftermarket alternator.
- Verify if your van has an internally or externally regulated alternator before ordering a replacement.
- For stock electrical systems, a quality new alternator from ACDelco or Bosch is a reliable choice.
- If you have added accessories, upgrade to a high-output alternator from a brand like Powermaster and consider upgrading your main power wires.
- This is a straightforward DIY replacement that most owners can perform with basic tools in under two hours.
Is Your G1500's Alternator Failing?
The charging system in these classic GMC vans is straightforward, and so are the warning signs of a failing alternator. If you notice your headlights dimming at idle, a red 'GEN' or 'BATT' light on your dashboard, or a whining/grinding noise from the front of the engine, it's time to inspect your alternator. A battery that keeps dying, even after being charged, is another strong indicator that the alternator isn't doing its job. Sometimes, a failing alternator can also cause strange electrical issues, like the radio cutting out or the heater fan slowing down.
Common Ordering Mistake
Early models in this generation (around 1979-1984) may have used an externally regulated alternator. Later models switched to a more modern, internally regulated design. When ordering, it is critical to visually check your current alternator. An externally regulated unit will have a separate, small box (the voltage regulator) mounted on the firewall or fender well. An internally regulated alternator does not have this separate box. Many owners of older models choose to upgrade to an internally regulated alternator, which requires a simple conversion wiring kit.
Choosing the Right Aftermarket Alternator
For a vehicle from this era, finding a brand-new OEM Delco-Remy alternator is nearly impossible. The aftermarket is your best and most practical source. The good news is that many aftermarket brands offer quality that meets or exceeds the original specifications. Your choice depends on your budget and how you use your van.
Brand Tiers for Your G1500
Premium Brands (ACDelco, Bosch):
- ACDelco: As a GM-backed brand, ACDelco is a top choice for fit and performance. Their Professional (Gold) line is highly regarded for quality and reliability, making it a safe bet for a direct replacement.
- Bosch: A well-respected German manufacturer known for high-quality electrical parts. A new Bosch alternator is an excellent, reliable option that often provides long service life.
High-Performance Brands (Powermaster, Proform):
- Powermaster: If you've added electrical accessories like a large sound system, extra lighting for camping, or other equipment, a high-output alternator is a smart upgrade. Powermaster specializes in these and is made in the USA. However, some user reviews show mixed long-term reliability, with some units failing prematurely. These often require wiring upgrades (known as the "Big 3" upgrade) to handle the extra power.
- Proform: Similar to Powermaster, Proform offers high-amperage alternators for vehicles with higher-than-stock electrical demands.
Standard Replacement Brands (Remy, WAI Global, BBB Industries, MPA):
- Remy: With roots in the original Delco-Remy, this brand has a long history. Their new and remanufactured units are generally solid, standard replacements.
- WAI Global, BBB, MPA: These brands offer a good balance of value and performance for a daily driver with stock electrical needs. They are widely available and provide a cost-effective solution to get your van back on the road.
Pro Tip: Consider an Amperage Upgrade
The original alternators in these vans had low output by modern standards (often 63-78 amps). If you plan to add any modern electronics, even just a new stereo and phone charger, upgrading to a 100-amp or 12SI-style alternator is a popular and worthwhile modification. This provides more power at idle and ensures the system isn't overworked.
Cost of a New Aftermarket Alternator for a 1979-1988 GMC G1500
| Part Type | Price Range |
|---|---|
| New Aftermarket (Standard Output) | $47 - $150 |
| New Aftermarket (High Output) | $150 - $440 |
| Shop Labor | $100 - $225 |
Frequently Asked Questions
Can I replace the alternator myself?
Yes, this is a very DIY-friendly job for a 1979-1988 G1500. The alternator is located at the top front of the engine and is easily accessible. Basic hand tools are all that's required, and the process typically takes 1-2 hours. Always remember to disconnect the negative battery terminal before starting work.
Do I need a new or remanufactured alternator?
This guide focuses on new parts. New alternators contain 100% new components and often come with better warranties. While quality remanufactured units from good brands are a viable option, a new part eliminates the risk of underlying issues from old components.
What are TSBs or recalls for this alternator?
Searches for recalls and technical service bulletins (TSBs) on the NHTSA website did not find any specific issues for the 1979-1988 GMC G1500 alternator. Recalls found were for much newer model years and different vehicle platforms.
What does "1-wire" vs "3-wire" alternator mean?
This refers to the wiring connection. A "1-wire" alternator is a simple upgrade that only requires the main battery charging wire to be connected. A "3-wire" setup is closer to the original factory design, with extra wires for voltage sensing and the dashboard warning light. Many high-output and conversion alternators are 1-wire for simplicity.
Technical Specifications
OEM Part Numbers: 15200110 15288861 15263859 15847291
Varies by model year and engine. Common original alternators were Delco-Remy 10SI or 12SI series. Amperage ranged from approximately 63A to 78A. Check for internal vs. external regulator. Mounting points and clocking position are key fitment details.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.