The existing definition for pin8 is invalid.
I had to make this change in order to use the second fan driver for 'Extruder cooler pin'.
-#define FAN1 PIN 8 // (e.g. useful for electronics fan or light on/off) on PIN 8
+#define ORIG_FAN2_PIN 8 // (e.g. useful for electronics fan or light on/off) on PIN 8
-- Itai
I had to make this change in order to use the second fan driver for 'Extruder cooler pin'.
-#define FAN1 PIN 8 // (e.g. useful for electronics fan or light on/off) on PIN 8
+#define ORIG_FAN2_PIN 8 // (e.g. useful for electronics fan or light on/off) on PIN 8
-- Itai