That's certainly a strange one. I can't think of anything simple that's common to the two circuits. Is everything working normally otherwise, specifically:
- brake lights work and are evenly bright?
- chimes when lights are on and door is opened?
- chimes when the key is inserted and door is still opened?
- chimes for a few seconds when key goes to run and seatbelt is unfastened?
- (if not burnt out) seatbelt lights (one by a/c knob, one pointed at rear seats in center console) go on for a few seconds when key goes to run?
[I'm not sure if your '84 chime does all the above]
You could try the voodoo electrical cure of spinning all the fuses in place and see if it changes anything.
It's what cwazywazy says. Check fuse 6. If the fuse looks good, check the wiring to make sure that it's connected to the fuse. Also spin the fuse. On the cars with the time delay for the dome light, if the brake light fuse is out, the chime will go on when you depress the brake pedal. You may also notice the dome light coming on at the same time. The other thing is that the time delay will not work. My family's original 245GL did this. Fuse looked fine, but noticed that one of the wires wasn't installed completely on that fuse's terminals. Once I plugged that in, everything remained quiet and the dome light remained off, while the brake lights worked.
Unplugging the chime module will make it quiet, yes, but, at the same time will keep you illegal. I know that most TB'ers hate them with a passion, but they actually can be kinda useful in cases like this.
Yes, as the experts have said, check fuse 6 (your brake lights are not working at all). Hopefully, it's just fuse contact corrosion or a cracked fuse. If it's blown, you may need to figure out what caused it to blow.
I forgot about the delayed courtesy light circuits. Fuse 6 feeds both the brake lights and the courtesy delay light relay. When fuse 6 is blown, stepping on the brakes connects the brake bulbs to fuse 6, but without power, no brake lights. Stepping on the brakes also has the side effect of weakly grounding the fuse 6 connection through the brake light filaments to brake light ground. This weak ground goes through the courtesy delay light relay and weakly grounds the door switches. When the chime gets power from headlights-on, and a weak ground through the door switches, it's enough to set off the chime.
[BTW: as far as I could find, removing, or altering, the chime is not illegal in the USA. Selling a new car without a chime is.]