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So my airbag light comes on immediately after I start the car. I replaced the module behind the passenger airbag with a Ford Unit part# F5DF-14B056-AA which I had read would work just fine on the X300. But does it??? As I just replaced the module and started the car, Airbag light comes back immediately just as before. If i'm not mistaken the SRS system on the X300s is very simple. 2 crash sensors in the front left and right fenders, the module behind the passenger air bag. The driver and passenger air bags themselves and the clock spring???
I cannot communicate with the Airbag module with me Scan Tool (Autel Maxisys Pro)
Please let me know what is the most likely culprit here?!
Yes I did download that awesome manual. I just want to see where I can find those resistors around here. Radio Shack is no longer in business and I don't know where to find these resistors.............
This works by removing the airbag from the circuit
The way we tested them in the airlines was a total circuit , and you do not know for sure if the fault light is from a airbag itself without them tested
We didn't have airbags but other things like engine fire suppressant agent bottles , Emergency exit slide inflation , cargo bin fire suppressant
Brenden' s doc is a test for the system as a whole in a separate step 5 though
The way we tested them was as the connectors where installed but have a resistor inline with the firing pin to limit the current to not fire off the device
The size of this resistor ( in the form of a incandescent light bulb ) was unknown to me or anyone else coming along to do the job so it was a tool already made up in the tool room
Just to be clear on the tests for the Air Bags and the purpose of the resistors.
The Air Bag ECU looks for a resistance on the Driver Air Bag circuit and the Passenger Air Bag circuit. I can't remember the exact range it deems to be OK but it's something like 1.8 Ohms to 4 ohms (so we use a 2.5 Ohm resistor as being about middle of the range and allows a small margin for the wiring loom resistance).
The purpose of the tests is to substitute a known value resistor in place of each of the Air Bags (one at at time). Therefore if you had the light on with the actual Air Bag in place, but the light goes off when the Air Bag is replaced with the known value resistor, then we can assume that the Air Bag itself was causing the fault light.
If the warning light remains on with the known value resistor, then we can assume the Air Bag is not the source of the fault (unless there are other faults also)
The diagnostic document specifically states in Bold Red Letters in a bright Yellow highlighted box NOT to carry out tests with the Air Bags in Place.
Do you remove one air bag at a time and replace with the 2.5 ohm resistor? Or you unplug both airbags and substitute with resistors and then proceed to unplug and replace clockspring, crash sensors with resistors?
Read the diagnostic process very carefully. The easy way is to substitute two resistors.
One prior to the passenger airbag and one prior to the drivers clockspring and air bag. If the SRS/airbag light goes out you know that is the fault is in one of the airbags or clockspring.
Careful reconnecting one at a time will show which is bad.
If you still have a SRS light after substituting the resistors the problem lies deeper in the control unit or crash sensors.
I am going through this process at the moment in an X300
Bill Mac
MK1
MK2
S3XJ8
X300 (x2 don't ask!)
15 previous Jags MK5 to X308
yup I was thinking to do just that, replace the 2 bags with resistors, this way there's no danger of them deploying. If airbag light goes out, i'll keep it that way as I don't want to put a 10 year + old bag in it....
Do you remove one air bag at a time and replace with the 2.5 ohm resistor? Or you unplug both airbags and substitute with resistors and then proceed to unplug and replace clockspring, crash sensors with resistors?
Read the diagnostic document in full. My recommended sequence and procedure is in there in detail. It's not the only way, but in my view the most efficient.
Airbag Light On
