The infamous Ford air bag fault 27 code is rather well documented publicly by everybody but Ford. Ford wants you to take your vehicle to a dealer for repair. The cause of the fault is the indicator lamp for the passenger side airbag is burnt out. Doing a quick search online will yield lots of repair tutorials are shown for replacing the light bulb with another like one or with a 12v LED. Simple stuff, but all that required me to purchase something that I didn't have on hand. My solution was to use a standard LED and a separate dropping resistor. I had not seen anyone post this publicly before, so I wanted to document it. To set this up, I soldered in an LED where the light bulb was and then used a razor blade to cut a trace on the circuit board that went to where the LED got soldered. I then soldered in a resistor. I believe I used a 470k resistor, but the exact one will depend on your LED that you use. It does not mater which side of the LED you add the resistor to, but it does matter which way around the LED gets soldered. If it doesn't work, try de-soldering it and putting it in the other way around. I did notice one issue with my repair and that is that the LED glows dimply when the light should be off. This is not unexpected behavior, and could possibly be eliminated if I had used a higher value resistor. LEDs take very little current to turn on, and there is always some current flowing thru the lamp with this circuit in order for the system to monitor if the lamp is burnt out.
Follow-up from a couple years in the future:
I was involved in a crash in this vehicle in January 2022 because of icy roads. While my tuck was a total loss, the air bags deployed properly. The sketchy repair I made likely saved my life.
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