Don't let seat belt fool you

| Saturday, March 23, 2013, 12:01 a.m.

QI have a 2004 Chrysler Sebring convertible. Approximately three or four months ago, the seat belt warning light came on and stayed on for a short time and then went off and stayed off for a short period and now it came back on. Is there an easy fix for this problem, such as a fuse, or is this something that will have to be addressed by a dealer? I don't understand why it goes off and then comes back on.

— David Garthwaite

AYour seat belt warning light is commanded on by the air bag LED warning control circuit within the instrument cluster when it sees a closed driver's side seat belt buckle switch. The buckle is part of the seat belt tensioner, which contains a pyrotechnic device and mechanism which almost instantly snugs the seatbelt during a crash. This can help prevent occupants from sliding beneath the seatbelt and helps to keep driver and passenger in the best position for airbag deployment.

Did the seatbelt warning light illuminate or go off while driving, with the seat belt already buckled? Or perhaps it remained on for an entire driving session, but not the following day? If the first case, I'd suspect a possible connection fault in the seat belt sensor circuit connector beneath the seat or the buckle switch. In the second case, perhaps foreign debris within the buckle cavity is confusing the switch or wear within the buckle is causing intermittent switch function. Try inspecting, and perhaps vacuuming the buckle cavity, and exploring deliberate movement of the buckle connection with one eye on the light.

The tensioner/buckle assembly is a fairly pricey part. If you are unable to find relief by cleaning the buckle cavity, I found a place that repairs tensioners for about $60: Safety Restore, at 855-552-7233 or Removing/reinstalling the part appears fairly easy and they offer expedited repair and shipping times.

I searched hard but was unable to come up with conclusive information on whether an open seat belt switch affects tensioner or air bag deployment. My hunch is it could, making this a high priority repair.

Q I own a 2008 Chevrolet Equinox. After owning it for about 2 years, using the same gas, the “check engine” light kept turning on and off for several days at a time. The dealer said the scan indicated lean fuel. I tried higher octane. I began using Chevron gas, and the problem remained. The light continues to turn on for two or three days and goes off for two or three days. Any suggestions?

A It's the Chevy, not the fuel. A lean mixture trouble code indicates either one or both cylinder banks are producing excessive exhaust oxygen, which means there's too much air or not enough fuel for proper combustion, or air leaks after combustion.

Were there two codes, P0171 and P0174, indicating low voltage in both cylinder bank O2 sensors? This could be caused by a contaminated mass air flow sensor; air leak in the mass air flow duct; vacuum leak; low fuel pressure; or restricted fuel filter. If only one of the two codes is present — meaning one O2 sensor only — the cause may be a faulty oxygen sensor, dirty fuel injector, vacuum leak, misfire or exhaust leak on that cylinder bank.

Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at

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