WIPER SOLENOID VACUUM CONTROLBACK ORDERED SORRY-THESE ARE ON BACK ORDER FROM THE MANUFACTURER. WILL PROBABLY BE LATE 2015 BEFORE THEY ARE READY.Use WSW321 as a replacement.The unit mounts on back side of the tachometer - when energized from wiper switch this unit blocks vacuum flow to the control side of the wiper relay valve, which in turn directs main vacuum to flow to the actuator (opens door)original GM # 5638276 MakeCHEV ModelCORVETTE Year1968-1972 Item#WSW320 Instructions / Core Return FormClick Here Price$69.95EACH Core Charge$0.00 QtyAdd