The system is very sensitive to resistance (oxidation/dirt) on the connectors. A fault is flagged if the total resistance on the Air Bag is more than 4 ohms. I have seen faults clear permanently just by unplugging and plugging in again.

I suggest first step is to use contact cleaner on the connectors as that may be all that is needed now.

 

You have 4 black box devices between the headlight pairs , 2 for headlight current sensors ( light inoperative dash light ) and the yellow conduit for the crash sensors , while you are there , spray some WD - 40 in the horns and not a penetrating spray as you want to leave a lubricant behind for the air driven horn

Yep , some digging to do