To find the correct fuse(s):
1. Consult your owner's manual: This is the best resource. It will have a diagram of the fuse box showing which fuse controls what.
2. Check the underhood fuse box cover: The inside of the cover often has a diagram showing the fuse layout.
3. Look for fuses labeled "TAIL," "STOP," "PARK," or similar: These labels might indicate the taillight circuits. Remember, it's likely to be more than one fuse.
If you can't find it in the underhood fuse box, there might be a secondary fuse box inside the vehicle, but this is less common for taillights. Again, your owner's manual will be your best guide.
If you're still having trouble, taking your Astro to a mechanic or auto parts store is recommended. They have access to wiring diagrams and can easily diagnose the issue.