Well, after spending some fighting under my driver side dash, trying to locate this module, I finally checked the passenger side. Lo and behold, it was sitting right there, behind the passenger glove box.

So, thought I'd write a quick post, should someone need this info, and find it while searching. I can only guarantee this applies to the '94 Camaro (V6). I suspect it will also apply to '93 and '95, but cannot guarantee that. '96+ is probably different.

There's many possible problems that could activate your airbag light, including that parts of your airbag system have been removed or damaged. If you changed your steering wheel, recently poked around under the dash, or dropped your steering column, you may have damaged something.

But if instead your light came on after something innocuous, like getting a jump start, a dead battery, a stereo install, etc., it could be the diagnostics module was damaged.

On the '94 Camaro, it's known as the DERM. (P/N 16176558), and is located behind the passenger glovebox. It's a metal box about the size of a typical ECU/PCM, has a sizable (20+pin) yellow connector, and sits behind the glove box. If you fold down the glove box all the way (bypassing the hinges), you'll see the metal top of the DERM and the yellow connector on the left.

The DERM contains circuitry to test all the air bag system components (check for continuity, or lack thereof, and proper resistance values). It also contains a battery, such that even if the fuse for the air bag system is removed, it may still fire the air bags. It also tends to be cranky and sensitive to electrical gremlins. Low voltage may overtax an aged DERM, and cause it to fail.

If you've gone thru your car and can't figure out what's causing your air bag light, before you try replacing sensors, replace the DERM. It's easy to get to the connector, to plug in a known working unit, so is easy to confirm fault.

It may also be possible to get a diagnosis thru the OBD port, though this may be tricky on the '94/'95 Camaro, and a "regular" (read: cheap) code scanner is unlikely to find anything, anyways. I'm unable to confirm that it's possible, but I suspect GM built something in, so dealers could identify a faulty sensor/bag quickly and easily. (Then again, who knows.)



If it's not the DERM, then it is probably either a faulty sensor (unlikely), a missing/damaged air bag (possible), or you damaged the coil on the steering column, while it was lowered. If you lowered the steering column, and turned the wheel, it probably caused your problem - do some reading. Header installs may be a common occasion for this to occur.

Many common air bag systems use electromechanical sensors; there's a small ball inside a box, attached to a magnet at one end. If you decelerate suddenly enough, the ball will break loose of the magnetic field, and electrical contact will occur (either because the ball isn't shorting the circuit, or because the ball moves to join a set of contacts.) These sensors are typically open by default; a continuity test should show no connection. (Ohm-meter will show infinite.)

There's two kinds of sensors in the '94 Camaro, an arming sensor (above the transmission tunnel, under the center console, where your armrest is), and two impact sensors, one by the steering column, the other up by the radiator. To deploy the airbags, the system wants to see both the arming sensor, and an impact sensor, go hot.

On many airbag systems, if one sensor is hot when you turn on the car, it will NOT disable the airbags, but instead place them in a half-cocked position. Essentially, the two types of sensors acts as a double-check safety, and you no longer have that double-check. It may cause the system to be more sensitive to impacts, and would also cause it to deploy if a single additional sensor (of the other type) failed - two impact sensors failing wont deploy, only an impact sensor _and_ an arming sensor.

While I find it unlikely that the air bags will deploy while doing diagnostics, I always keep my head clear of the firing line, and tend to be on the nervous side. I suggest that if you're doing work near the air bag system, that you do the same. My Chilton's manual recommends removing the fuse for the air bag system before doing work near it, but do note, the DERM still contains a backup power source, which could trigger the air bags - even if the main battery is disconnected.

Disclaimer: Please note that I do not know what type of sensors the Camaro uses, that it may vary from year to year, and that I am not providing instruction on servicing your air bag system. If your air bag light is on, you follow the directions in your owners manual, and probably take it to a bonded and insured mechanic who is qualified to work on the air bag system in your car.