What do you check when the Inflatable Restraint light stays on in the dash of a 1992 Corvette?

My best guess (and only a guess) is an electrical disconnect somewhere. I once had a corroded module in a van....once the module was changed the light went out. But unless you know what to touch on a C4 I would be very wary of probing around for a short.

If it were my car I would take it to a REAL auto parts store (not a national chain) and try to find someone who knows about these things. If nothing else they can possibly advise you where to take it. I try to avoid dealers.

Both, the Inflatable Restraint (Air Bag) light and the Seat Belt light stayed on in mine. Owners here advised me to remove the 2 sensors (one on each frame rail), clean the rust off of the rail and the back of the sensor, apply a conductive rust/oxidation inhibitor, and re-intall. I replaced the old, rusty screws with new stainless steel ones. If the light(s) stay(s) on, then the sensor is bad.
On the right frame rail, condensation from the A/C drips directly on that sensor. Not good. I believe a forum member said he affixed a piece of rubber (bicycle inner tube ?) over the new sensor.

The exact location of the sensors might be different on your '92 than on my '90. Hope this helps you, though.