This multi-ribbed belt drives the air-conditioning compressor from the engine crankshaft. It transmits torque through multiple V-ribs on its inner face, which engage with matching pulleys on the compressor and tensioner assembly. A worn or glazed belt slips under load, reducing compressor output and causing the cabin climate system to blow warm air. The original belt is molded to the same rib profile and length as the factory assembly, so the tensioner maintains its correct operating range without over-travel. On replacement, inspect the tensioner pulley for bearing wear and replace the belt if any cracking or fraying is visible on the ribbed face.