To find the solution, I recommend these steps:
1. Consult your owner's manual: Check the diagrams and troubleshooting sections. It *might* show the relay's location, or at least point you towards the BCM.
2. Check online forums and repair manuals: Search for "2000 Chevy Astro power door lock relay location" or "2000 Chevy Astro BCM location" on forums like Astrovan.com or repair manual websites like Chilton or Haynes. These often have detailed information from other owners who've tackled similar problems.
3. Locate the Body Control Module (BCM): The BCM is the most likely place the power door lock function is controlled from. This is usually under the dashboard, sometimes behind a panel near the steering column or under the glovebox. Finding the exact location may require some careful searching and possibly some panel removal (be careful not to damage anything). Once you find it, the relay might be internal and not replaceable individually.
4. Professional help: If you're uncomfortable working with car electronics, a qualified mechanic will be able to diagnose and fix the problem much more safely and efficiently.
In short: Don't expect a simple "it's here" answer. The system is more integrated than in older cars. Your best bet is research using the model year and specifics about your issue (e.g., "driver's side door lock not working") to refine your search on automotive forums.
