My US-spec 780 has a key-in-ignition chime; they added a chime relay for US market cars. There's a space for one on OZ-spec 740 / 940 relay cradles but it's not fitted, and OZ-spec cars may not be wired for it.
I got one of these chime relays on Ebay for repurposing as a low coolant warning chime. Some of the coolant expansion tanks on 940s are fitted with floats for the low coolant sensor, but the sensor itself isn't fitted. 960s were fitted with these sensors as standard equipment.
The seat belt warning light uses the indicator flasher can, and it's (usually) mounted in the front of the centre console in 240s, just behind the plastic facade. The flasher can in 740s / 940s is in mounted in the relay cradle behind the ashtray and under the equaliser / small storage shelf below the radio, so the clacking sound is a bit more muffled compared to a 240.