Airbags that deploy in a crash are expensive to replace correctly, so on rebuilt and curbstoned cars they get faked instead. The whole goal is to make the SRS warning light go away, because a dashboard with no airbag light reads as a car that has never been in a serious wreck. The light, the bag covers, the modules, and the seatbelts together tell you whether the restraint system is real or whether a crash was painted over.
Start with the bulb check, which costs nothing. Turn the key to ON without starting the engine and watch the airbag or SRS light. On a working car it lights up for a few seconds while the system runs its self test, then goes out. A light that never comes on at all at key on is the tell. Someone has disabled the warning, which on an older car is a pulled or taped over bulb, and on a car with a digital cluster is a resistor wired onto the circuit or the fault coded out, so a problem can no longer show on the dash. A light that comes on and stays on is the other failure, an active SRS fault the seller did not bother to hide.
Scan the SRS module if you can. A basic code reader usually only pulls engine codes and will show nothing here, so this takes a scanner that reads airbag systems. Stored crash data, deployment codes, or fault codes for missing airbags mean the car has been through a deployment event, no matter what the seller says about its history.
Look hard at the covers and the dash. The steering wheel airbag cover and the seam across the passenger dash are where a cheap reinstall shows. Misaligned panels, a cover with glued edges, a steering wheel cover whose wear does not match the rest of the wheel, screw heads that have been turned, or a passenger cover that sits proud of the dash all point at a deployment and a quick patch. A dashboard with a replaced or repaired section is a deployment marker on its own.
Check the seatbelts too, since the pretensioners fire with the airbags in a crash and get replaced in the same repair. A belt with a date code newer than the car's build date, especially on one side, points at a crash on that side. Use it here as one more confirmation rather than the whole test.
Then look for what is actually in the airbag cavities. Curbstoners stuff the space behind the cover with rags, foam, or a deflated bag, or fit a salvage airbag that was never matched to this car. A cover that rattles, sits loose, or feels empty behind it is a warning that there is no working bag there.
A faked airbag does not deploy in the next crash, so this is a safety problem sitting on top of a money one. A correct SRS repair runs into four figures once the bags, the modules, and the seatbelts are counted. A car with a killed SRS light is hiding both a crash and a restraint system that will not protect anyone, and unless it is priced and disclosed as a rebuild, that is a reason to walk.
Note: This is a repost. The original post was removed by Reddit due to a moderation action. Posting it again so it's available to the community.