Located undernieth the ABS modulator is this switch pack or shuttle valve switches, seucured by three screws. This is the part that fails, in the past that meant replacing the complete ABS modulator at great expense.

The brake fluid lines do not have to be disconnected. No need for bleeding procedure (which on these vehicles requires computerised bleeding)

Unclip the brake lines along the bulkhead, this will allow them to flex upwards.

Undo the modulator mount fasteners

Raise the modulator assembly upwards and tie it up as high as it will go (attach strap to bonnet, tie to strap)

Remove three screws under the modulator securing switch pack

Pull switch pack downwards and disconnect wiring plug from circuit board, be gentle or you will pull the pins out of the circuit board.

Fit new switch pack.