System B Disabled (Maintenance Mode) by Hardware A/B Switch

Figure 1. Dual‑System B Disabled (Maintenance Mode)
Auto Switch Green
A B
Off Select Off
Green/Gray Ready Green/Yel
Green Active Off

The yellow bezel of the Ready light indicates that maintenance personnel have disabled system B.

Action

To make system B ready for operation set the hardware switch to enable B (that is, to allow automatic switching).