My 92 190E2.6 with 90K miles has started to drop out the compressor. At first it was intermittant but now it is often. The unit is charged and the signal for the compressor clutch is good through the low pressure switch. Applying voltage to the clutch brings the compressor on line. I am suspecting the MAS module or the feedback tach on the compressor. I have reseated all connectors and MAS module. I am planning on scopeing the tach signal later but will bypass the the MAS module temporally to allow AC to work. What is the most likely component to fail(Compressor tach or MAS)?