Dear Tom and Ray:
I live here in England (my wife is from New Jersey, and she introduced me to you guys). Recently my wife and I drove our "eBay special" Renault Laguna to Twickenham in Surrey. We parked not far from the river and went for a coffee. When we returned to the car an hour later (it was a dry day), the whole street was under water. Our Renault was in about two feet of water. The car started and I backed it out whilst the locals watched me and shook their heads. After drilling holes in the foot wells, we drove home. We got the car dried out at a garage, and the engine is fine. However, the seat-belt pre-tensioners got soaked, and now the air-bag light flashes constantly. The garage could not do a diagnostic of the air-bag system on this 12-year-old banger. Do you think there is a danger of the air bag going off whilst driving? Cheers!— John
Tom: Quite the opposite, John. I think there's a danger that the air bag will not go off if you have an accident.
Ray: I'm just impressed that he happened to have an electric drill in the car, just in case he needed to put drain holes in the floor. Now, that's planning ahead.
Tom: When the air-bag light is flashing, John, that means there's a fault somewhere in the system. The car's computer runs a self-diagnosis every time you start the engine. The flashing air-bag light is telling you that the computer detected a problem, and you can't count on the system to work properly.
Ray: The seat-belt pre-tensioners are part of the air-bag system, or more correctly, the supplemental restraint system (SRS). They use small explosions to instantly cinch up the seat belts in preparation for a crash, to pull you into the correct position, where you can most benefit from the air bag.
Tom: You might talk to a collision repair shop, which would have experience in rebuilding cars after accidents involving air-bag deployments.
Ray:: But I'm not certain that's all that's wrong.The air-bag sensor itself could have been under water, too.
Tom: So before replacing anything, I'd try to find a mechanic who can perform a proper scan for you. That may require a trip to the Renault dealer. And if you're thinking about returning to Twickenham, you might consider having the dealer install the official Renault bilge-pump and pontoons while you're there. Good luck, John.