Bill nailed fuse 13 as the suspect circuit. If it turns out fuse 13 looks intact then pull it (as in remove it) to make sure the ends haven't worn through -it can be deceiving. If the fuse is okay then it could be the ignition switch. The hot side of fuses 11, 12 & 13 are on pin 15 of the ignition switch. With the ignition ON (KP-II) check for 12 volts on those fuses. If none have 12 volts then it's likely the ignition switch, otherwise the problem is likely elsewhere in the fuse 13 circuits. If you don't have a meter handy then if either the backup lights still work (fuse 12) or the dash indicator still lights when you set overdrive (fuse 11) then the ignition switch is okay, otherwise suspect the switch. It's simple to replace with two slot screws holding it to the back, but a pain to access the screws and see what you're doing. Best to remove the instrument cluster and access from above using a light and mirror rather than try from under the dash.

Your 1984 wiring diagram green manual can be found here in the OzVolvo archives
https://ozvolvo.org/archive
Type 1984 into the search field to find it.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now