The relay is for
Australia TCVASIt used water temps, instead of air temps. TCVAS was disabled when engine coolant temperature was low, using this thermostat bolted to manifold side of cylinder head at the front

TCVAS is important as it reduces pollution. On the other hand if its not working performance doesn't suffer neither does fuel economy.
Transmission Controlled Vacuum Advance System (TCVAS) disables spark advance except in Top Gear. Since this "retarded" spark timing reduces performance, to prevent cold-engine driving problems this system is bypassed in cold temperatures. This means vacuum advance works normally at cold temperatures. Additionally, onn the highway (in top gear) full power is always available
Top Gear Switch

Does your 1985 ute have something like this on the intake manifold? Post your pics and I will add them to the tech article