To find it, you should:
1. Open the hood.
2. Look carefully around the lower portion of the engine block. The cord will typically be a heavy-duty cord, often black, and may have a connector that's plugged into the engine block itself.
3. Check near the oil pan and the lower radiator hose. These are common areas for block heater placement.
4. Look for a small, weatherproof cap or grommet in the firewall where the cord exits the engine bay. This can help you trace the cord back to the heater itself.
If you're still having trouble locating it, a quick online search for "2001 Chrysler 300M block heater location" along with images might be helpful. Also, consulting your owner's manual could provide a diagram or description of the block heater location.