* Haynes Repair Manual or Chilton Repair Manual: These are readily available at auto parts stores, online retailers like Amazon, and sometimes even libraries. They usually include comprehensive wiring diagrams. This is often the most cost-effective option.
* Factory Service Manual: This is the most detailed and accurate source, provided by Buick/GM directly (though obtaining one might be challenging now). These manuals were expensive even when new and are usually only found through used booksellers or online auctions. They often contain much more information than Haynes or Chilton.
* Online Forums and Communities: Websites and forums dedicated to Buick or GM vehicles (like Buick forums or general car repair forums) may have members who have scanned portions of wiring diagrams or have experience with the 1991 Regal's electrical system. Searching these sites for "1991 Buick Regal wiring diagram" might yield some results. Be aware that the quality and accuracy can vary.
* AllDataDIY or Mitchell OnDemand: These are subscription-based online resources used by professional mechanics. They offer extremely detailed wiring diagrams and other repair information. However, they require a paid subscription.
Important Note: When using any wiring diagram, be absolutely certain that it matches the exact year, model, and options of your 1991 Buick Regal. Even minor differences can lead to incorrect wiring interpretations and potentially damage your vehicle.
Start with the Haynes or Chilton manual; it's the most accessible and likely sufficient for most tasks. If you need something more comprehensive, look into the factory service manual or online professional resources. Remember to always disconnect the battery's negative terminal before working with any electrical components in your vehicle.
