Struggling a bit with this sim. I know you have to be surfaced to use the radar, but is there anything else that needs doing? I'm going to the radar whilst surfaced and cannot get it going. I can alter range knobs etc, but the "on/off" toggle lights up but refuses to move. Funnily enough, it works fine in the sub "school", but not in campaign. And I REALLY need it

. Any ideas?
PS it is patched to 1.4
Cheers, Andy