That solenoid is actually not what you would find on an 86.

The 85 solenoid has 4 terminals, but only has wires on three of them.

The red/lt. blue wire needs to be on the small terminal labeled S.

Usually the front big terminal is used as a power distribution point and has battery voltage at all times, and several wires on it.

Normally the rear big terminal has a single wire on it that runs down to the starter mounted solenoid trigger terminal.

Down beside the voltage regulator you should have another relay that looks the same as your starter relay, that one is the glow plug relay.