B.C. says, " Older models, and maybe yours, have an additional spade lug terminal. Use of it ended in 1982, I think."

It's called a "Service Socket", used by mechanics to "bump" the starter by using a jumper wire from the battery. It's shown in the '87-'88 factory diagrams, and exists on my '93 940, so I'm sure you have it too. Finding it is the trick.

Look around the upper firewall, a bit to the left of center, for a short (5"-6") Blue wire coming out of one of the horizontal wire bundles there, it will have a black plastic end insulating a female spade terminal. Also a red plastic sleeve with a wire ID # just behind the plastic end cap.

A jumper from Battery+ applied to this service terminal will cause a good starter to spin and engage -- as long as the battery is up and the main cable connections are good at each end.
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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.