My gate drive does has stopped working and the “danger” indicator light is a constant orange.

If the danger indicator remains lit constantly, there is a problem with the cells or the shunt (electrical wire) connected to terminals 3 and 4.
If you have cells:
1. Check that the indicator light in the receiver cell (the one with 4 or 5 studs and not the one with a kind of LED which isn’t in fact one) is lit red constantly.
For your cells to be functional, this indicator light must come on.
If it is not lit, check: that the cells are aligned and are clean both inside and outside.
2. If the cell indicator light is on and the DANGER indicator on the unit is lit, there is either a problem with the cells or a problem with the connections.
In this case, perform a shunt between 3 and 5 in the receiver cell.
If the DANGER indicator light goes out, you have a problem with the cells.
If the DANGER indicator light does not go out, perform a shunt between 3 and 4 after disconnecting the wires on terminals 3 and 4.
If the light goes out, this means that you have a connection or alignment problem (see 1.) with your cells.