The NEW AC Heater Climate Control Module 599-211XD is a black, bolt-on HVAC control module designed for Chevy and GMC vehicles. Made of durable plastic, this automatic control module features 24 terminal pins divided into 2 plugs, making it easy to install with the included package. With interchange part numbers like 599211XD and compatibility with OE/OEM part numbers like 599211, this improved design module offers durability tested performance without the need for drilling or modifications during installation.