Originally Posted by 69MustangCoupe393cid
I'm not sure I understand what proving out the system is. I don't get any chimes or anything when I turn my key on. Just the flashing of the airbag light which than turns solid when it's done with its test. Does proving the system reset anything? Or am I supposed to pull the bags and put those fakes in and see if I get the same error (which would prove my bags are ok)?
It does not reset anything, it is just the standard test that happens every time you start the car--you will not hear any chime unless the "air bag indicator" (the light) is inoperative. The system fault is indicated by the light's staying on as you indicated above.
However as in your original post you indicated you observed LFC (Lamp Fault Code) 19, I would not expect the system to "prove out" (self test) until the RCM is replaced. (Note that the LFC only reports the most serious code, there may be others that will be indicated when the highest priority problem had been fixed.)
The purpose disconnecting the air bags and plugging the the resistors into the harness it to to make the RCM believe the airbags are connected--so that after you replace the RCM, and perform the prove out, they will not detonate if some serious fault remains (or has been created during the repair).
that detonates the air bag has a resistance of 2.3Ω if it is intact and "ready to blow". The RCM passes a small current limited test signal (just a few ma, it takes 5+ amps to light up the squib) through the squib to detect this resistance, and confirm that the air bag is connected and ready to go.
By placing the resistors across the harness connectors the RCM believes the air bags are there and "good to blow" while doing the test--a bit safer than doing the test (after the repair) with live explosives.
If the RCM does try to detonate a bag the resistors in place they will just go "poof", that's why using 1/4W resistors is a good idea--two 4.7Ω 1/4W unit in parallel can handle 1/2W maximum power, if the RCM tries to apply 5.0A at 12.0V that will be 60W and the resistors will go "poof"--not enough to start a fire or anything, just a pop and bit of smoke (don't ask how I know)...
It can be difficult to find the 4.7Ω resistors locally, but you can get them for next to nothing on eBay
When soldered in parallel to make the 2.3Ω value they will look like this:
Reshape the twisted/soldered leads to fit the harness connector.