To find it, you'll likely need to:
1. Check under the dash: Look carefully along the driver's side, especially in areas where wiring harnesses are bundled.
2. Consult your owner's manual: This is the best resource for the precise location in your specific vehicle.
3. Look for a small, usually square, black box: The inertia switch often has a button that can be pressed to reset it.
If you can't find it after a thorough search using these methods, it might be worthwhile consulting a Dodge Ram mechanic or automotive repair shop.