There are two front crash sensors, one near each headlight and a few inches below them. Just for you, I dragged my Dynasty out of storage to double-check since I never had to work with these. They're more of a body shop thing.
The crash sensors are about 1 1/2" black cubes held on with three 10mm bolts. My Dynasty wasn't available with the outside thermometer, so I have to do this from memory according to the sensors used on Caravans. The sensor you're looking for is a small black round cylinder about 2" long and 3/4" in diameter. The sensing element sticks out of the end opposite the two-wire connector. That element is about 3/16" in diameter by 3/8" long. This sensor, as I recall has a wing molded on to run the mounting screws through. I think they were 8mm bolts, two of them.
The sensor is real easy to see behind the center of the grille on Caravans, but where I would expect you to find yours is hidden by a panel. I think you will see it if you look up from underneath and behind the bumper. I would like to suggest it is bolted right to the grille, but I'm not sure. Seems to me you should be able to see it if you peek through the grille, right in the middle.
On a related note, to set your mind at ease, for the air bag to pop, either one of those front sensors AND the "safing" sensor inside the air bag computer must trip at exactly the same time. The angle of all three sensors is critical to insure the system won't deploy at too low of a speed. Banging on a sensor won't set the bag off. What you should not do is unplug one of them when the ignition switch is on. The computer monitors each front sensor for wiring problems. It can set four different diagnostic fault codes based on readings on just two wires. One of those codes, related to an open circuit, will be set when the sensor is unplugged, and the computer will turn on the red warning light and disarm the system.
On some cars, the system will rearm itself after the plug is reconnected and the ignition switch is cycled off and back on. There are some models that will not reset until the code has been read and erased with a hand-held computer called a scanner. The dealer can reset the computer. Aftermarket scanners used by independent repair shops can never do as much as the dealer's equipment, although they are getting better, but most can't access the air bag computer.
Friday, March 26th, 2010 AT 12:40 AM