Four Seasons' CLT1 EVC Compressor Drive Tool, No. 69635, helps technicians to analyze the root cause and conduct the correct diagnosis of a clutchless technique to make sure the valve reacts properly to steering signals, before opening the AC-loop. The tool helps figure out whether the malfunction is dependant on the electronics or the AC-Loop. It does not require any dismounting; simply disconnect the compressor cable and connect the tester. The CLT1 provides an answer within 15 minutes.