I'm trying to get it to work. I'm hoping someone can follow my logic here.

The light and chime has worked recently, although, intermittently. It appears to have stopped working completely in recent months.

Bulb test: When I had the gauge cluster out recently, I tested the bulb, and it's good. I also cleaned the contacts on the circuit board in the cluster. I wasn't trying to solve this problem at the time, so I didn't do any probing at the instrument cluster connector or circuit board.

Seat belt switch test: Per the wiring schematic, the seat belt receiver should be grounded when the seatbelt is unbuckled. I unclipped the wiring harness (2-wire) at the receiver base. With the connector unplugged, jumping the wires together on the body side of the harness should?, theoretically? cause the light to turn on (with the ignition on) and the chime to gong 5 times. This simulates unbuckling the belt/closing the circuit. This test failed.

Chime module/ convenience center test: Here's where I got a little lost.
First, I have 3 salvage chime modules in addition to the one plugged into the car. I tested all 3 in the car and the seatbelt light/chime isn't working on any of them. Either they're all bad (possible) or the problem is elsewhere. The audible chime definitely works for other functions.

I checked the pinout diagram for the chime module. I think? I can pinpoint the issue to the chime module if I am able to jump terminals on the plug-in for the module. But I'm not sure which ones. Should it be Seat Belt light (yellow) to ground, or seat belt switch (gray) to ground?

Pinout for the factory GM 14101255 convenience module, borrowed from eBay:



If I can jump terminals and make the light come on, then I think I've narrowed it down to a bad (lot) of chime modules. If I can't, then it's somewhere between the chime module connector and printed circuit board on the cluster?

One wonders why I'd even care - or not be grateful that the light/chime failed in the OFF position - but I'm restoring the car to factory original and everything must work to satisfy my OCD.