The 99 manual only shows the sensor/module under the console. No bumper sensors. It also says the module must be replaced after air bags are tripped. My suggestion is at least get a factory manual for your car and see what it says. I think the hamilton library has mitchell manuals for your car.
99 manual info:
Off GM Parts Direct Site:
1999 Camaro
1) Driver air bag
2) Psngr air bag
3) Psngr air bag Bracket
4) Diagnostic unit W/sensor <--there are 2 designs
6) Clockspring
1994 Firebird
1) Driver air bag W/o radio controls
2) Psngr air bag
3) Psngr air bag Bracket
4) Sensor Front
5) Sensor Arming
6) Sensor Pass compartment
7) Clockspring W/o radio controls
8) Diagnostic unit 1st design
Look at that, bumper sensor on earlier models. Most of the 97+ part numbers appear to be different, including airbags.
You should also verify any used parts you buy are the
exact same part number your car needs. The trouble charts include info about constant resistence measurement as part of the constantly monitored diagnostics.
My $0.02? This is not an amateur job. You need a scan tool to troubleshoot everything correctly. You can't even perform the basic diagnostic system check w/o it. Bags launching at the wrong time or not launching when they should is very bad. Don't be pennywise & poundfoolish.
And all the guys that have done it, do they know their system is really operational?