, Gloucester, MA

June 11, 2013

Why does air bag light turn on with no one in seat?

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Larry Rubenstein

---- — Q: I have a question regarding my 2005 Mercury Montego. My passenger-side air bag light turns on with nobody sitting in the seat. The light is supposed to turn on if a child is sitting in the front but does not weigh enough for the air bag to come on. But if an adult sits in the passenger seat, the air bag shut-off light is NOT lit as it should be. This just started today and never happened before. The vehicle has about 44,000 miles and runs perfectly. I did run over a speed bump moving fast the other day. Could this have caused the problem? Would it take a week for the light to come on?

A: This could be a very serious problem. The calibration of the seat could be way off. Or you could simply have an instrument cluster problem, which happens to be extremely common for your car. Before you get into major repairs, here is how I feel you should handle this problem, unless you want to go to the dealership.

Seek out a repair shop that uses a full-fledged scanner, not just a code reader. Read and record all codes in all modes. There are several computers in your car that need to be read, and a small code reader just won’t do it. After the codes are read and recorded, turn off the key and disconnect the negative battery cable for around two minutes. Reconnect the battery and start your car, and you may see that all is well. If the air bag light now works properly but you have a check engine light, simply clear the codes with a code eraser.

If all is well, you just dodged an expensive bullet.

If the problem is still present, a repair shop with a full Ford scanner, along with a skilled technician who is well-versed in Ford engineering, will be able to diagnose your problem, calibrate your seat and even update your computer with the latest software. If all the above work is done, you can expect to spend $200 to $300 for this repair.

Q: I have a 1997 Cadillac that runs very well. It has some dents and scratches on the outside due to a wide car with a narrow garage, but the interior is as clean as new. The problem is the exterior of the car. The car is a hardtop, but it has a cloth roof. The rear quarters have a very noticeable tint of green. How can I fix this problem? To replace the top would be a waste because the rest of the top is in perfect shape.

A: The problem may not be discoloring at all. Most likely, the problem is mold. A detail shop may have a product to clean the mold and restore the color. Have the detail shop test the chemical first in an inconspicuous location like the part the trunk lid hides.

Car Care Tip: As you start using your car in warm weather, the air conditioner may have a funky smell to it. Most of your auto parts stores and major chain stores have a deodorizer kit to easily repair this issue.

Larry Rubenstein is a master technician who owns a North Shore service station. His column appears most Tuesdays. Write to Larry at the Gloucester Daily Times, c/o Auto Scanner, 36 Whittemore St., Gloucester, MA 01930, or send an email to