Scan chains are used to detect faults in integrated circuits but with the size of today's circuits, it is difficult to detect and locate scan chain faults, especially when the scan data in and scan data out have been compressed. A method for debugging scan chains includes selecting a scan chain for debugging using a scan chain selection block and then providing scan test vectors to the selected scan chain. The scan test vectors undergo various scan test stages to generate scan response vectors. The scan response vectors are compared with ideal response vectors to identify a failing scan chain.