Q: A.c. pump is froze up, now car won't start

A seized a/c compressor can certainly make the engine difficult to start, if not start at all. To describe it in simple terms, the a/c compressor is similar to a mini engine. It can have chambers similar to engine cylinders and uses compression similar to the engine cylinders to compress the refrigerant. A seized or damaged compressor can make it similar to trying to start your engine AND a seized engine combined. The a/c compressor clutch can also be a cause. The clutch allows the a/c compressor pulley to spin freely when the a/c is not in use. If the clutch itself is seized and not allowing the compressor to spin freely, or the compressor cycling switch has constant power and not disconnecting the compressor from the clutch, this can mimic a seized compressor. Try disconnecting the electrical connector at the a/c compressor then trying to start the vehicle. If it starts, then the compressor clutch and/or electrical circuit is the most likely cause. If this doesn’t help, have a certified technician look into why the engine will not start to find the exact cause.