Input/Output (I/O) Signals
WARNING: This page is about a different car, the 1992 Subaru SVX, 1992 Subaru Legacy, 1991 Subaru Legacy, and 1990 Subaru Legacy. However, it is still accessible from the selected car via links, so may be relevant.
Check I/O signals (pin voltage) at cruise control unit connector. SeeFigure . If I/O signals are not as specified, repair circuit or replace component as necessary.