Blow-Up

An undeployed airbag is like a loaded gun; make sure your technicians take proper precautions under the dash and under the hood.


With such a priority being placed on vehicle safety, continued training on new safety technology is the cost fleets of all sizes are facing. The typical light duty vehicle has about 100 components designated to the safety system alone. Fleets are being forced to re-evaluate the level of...


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Any accessory that contains a power supply, such as a cellular phone, should be treated with caution. "The cell phone is sitting there in the cradle and even though you have disconnected the vehicle battery, there's still enough voltage in that system to accidentally deploy an airbag during maintenance," Hoffman says. "Radios will have internal batteries in them. You disconnect the battery, and the airbags could still be live for two or three days."

"Whenever we wire into our electrical circuits, technicians need to be sure that they don't tap into the wire that may feed the airbag circuit," says Hoffman.

"Between lights, radios and other accessories in fleets, if you tap into this circuit, it may cause the airbag not to deploy when it is needed because you are robbing power from the circuit," Hoffman says.

"If the installers tied into the vehicle wiring and weren't careful about what wiring they tied into, add-ons and accessories could cause a problem," Howe says.

"Generally those circuits are pretty well protected, due to the nature of the systems they're on. But it is still possible to be messing around in there and short wires together and deploy the airbag," he says.

"One thing they do recommend," Howe explains, "are airbag simulators. Essentially, it's a one ohm resistor; you plug it into the connector that goes to the airbag itself. It simulates the resistance of the airbag to test the system without actually having the airbag connected.

"After disconnecting the battery and waiting for the capacitors to discharge, you would physically pull the connector off the back of the steering wheel connector that goes to the airbag and plug it into the simulator," Howe says. "That way, when you are doing a diagnostic with a scan tool or an ohmmeter, it syncs that airbag in line?at least from a resistance standpoint. That way you can test your circuits, make sure you have a good ground, and make sure you have voltage where you are supposed to have voltage."

Placement of the accessories can be just as important to the safety of the driver as the safety equipment itself.

"Where you place your radios, where you place your computers, where you place the speaker for your PA system?it's so important today that it is not in the path of the airbag," warns Hoffman.

"We're putting the radios directly above the diagnostic monitor for the airbag which is between the seats on the floor. The signal caused from static electricity or the magnetic field being transmitted from the radio could accidentally deploy the airbag," Hoffman says. "So now you've got a guy going down the highway at 60 miles an hour, he keys up the radio to call his dispatcher and it blows out the airbag."

Solution?

Hoffman says the solution is as simple as putting an anti-static pad between the radio and the diagnostic monitor to block the magnetic field or static signal that is sent. Fleets can buy a rubber mat that just goes between them to block the signal. "I think it is something they don't have a clue about," Hoffman says.

EXPERT WARNING

"In my mind, you should NEVER put a vehicle back into service that does not have the full compliment of safety equipment, including all airbags and seat belt pretensioners," recommends Howe.

"If you are already performing body repairs on a crashed vehicle (or sending this out to a body shop), the cost of the airbag is relatively insignificant versus the body repairs. Most important, the lack of an airbag compromises the safety of the driver and occupants," he says.

"Also, you're going to create trouble codes unless you do some serious reprogramming to the vehicle electronics. The labor involved in the reprogramming would likely cancel out any cost savings for not replacing the airbag. While the airbag deployment circuits remain stand-alone (for safety reasons), the occupant restraint controller (ORC) and occupant classification module (OCM) do share data with the instrument cluster and other vehicle modules," Howe says. "Airbags are part of a system. By disabling a part of that system, it could affect all other safety devices in the vehicle," warns Hoffman.

"There is really a lack of training when it comes to why airbags and seatbelts work together," Hoffman says. "Location of accessories, clearing the path of the airbag-all of these combined could not only save fleets money, but could also save lives."

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