[Spridgets] '75 Midget brake question.

[Dave KK7SS]

The car has been parked outside all winter (covered)
Brakes were working fine when parked just before winter set in.
This weekend, getting ready for spring, I discovered the brake pedal goes all the way to the floor.
The reservoir is 1/2 full (both sides)
No signs of leaking brake fluid anywhere.
The red Brake warning light is lit.

Any suggestions welcomed.
Also input on how to reset the "shuttle" in the brake cicuit

Thanks

Dave G  KK7SS
DN06ig

'65 Sprite - in process
'75 Midget - driver