Gehl RS8-42 Parking brake not engaging

I've got our gehl in the shop for the parking brake not working from what I'm told. I have power to switch and sounds like power to the flow divider but it won't "grab" when i let go of brakes. any ideas? I've bled the brakes, filed the resivours and look at about everything. im not sure where solenoid is at either.

Gehl RS8-42 Parking brake not engaging