When evaluating automotive connectors, you must prioritize Current Rating (Amperage) and Voltage Rating to ensure they match the vehicle's electrical architecture. Key physical specs include Ingress Protection (IP) ratings, such as IP67 or IP69K, which are essential for connectors exposed to moisture or high-pressure cleaning. Additionally, verify the Operating Temperature Range, typically requiring -40°C to +125°C for engine bay applications, and ensure the Contact Resistance is low to prevent overheating.