The flashing AC light is indicating a fault in the AC system. It has its own self-diagnostic function which does not need a code reader.
The attached shows how to use it. Ignore the heading "1997 Volvo 960" as it also applies to the S/V90.
Work was good - retirement is better.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.