1993 Mercury Grand Marquis Air Bag Code 24

[friskyfrankie]

Can I assume the "blue" connectors are part of the air bag safer sensor? This photo was posted almost 10 years ago but is perfect to illustrate the issue. Not sure how it is mounted but hopefully will get to it soon. I know some folks have cleaned the mounting bracket, mount and bolt and STILL get the same code. Wonder if the systems still works with this code? So, two questions for this post!

[sly]

I think so. IIRC, that is the one. When you clean it, give the female connectors a slight pinch.

[friskyfrankie]

I only disconnected the connectors and sprayed contact cleaner into both parts, with no effect. Does it share a common ground or is it have it's own ground? Is there a bolt holding it to the framing behind it? Didn't look at that part so hence the questions. Not sure you can get a needle nose plyers in there to pinch them - perhaps a "dentist pick" to try to close them?

[friskyfrankie]

IIRC there is a ground wire/bolt at the bottom front of the driver's kick panel. Wonder if that is the only ground in the area for the sensor and other items which would mean taking the sensor off is unnecessary?

[sly]

I think the safing sensor is a metal case and grounded to the bolt it's mounted with. But since I've never pulled the one in my car, I can't say for sure. It's supposed to be similar to the impact sensors at the front and I know those are grounded through the case.

[friskyfrankie]

Yes, the front impact sensors are grounded through their cases but if I have the correct part I believe to be the safing sensor, it looks merely like a two part plastic sensor and unless it is grounded through the heavy plastic assembly it sits on (haven't removed the entire assembly) I have no clue how it is grounded. Schematic says it is grounded and there is no indication it is grounded through wiring so it would have to be grounded into the kick panel. This would require removing the entire plastic mounting frame and all the connectors that mount to it. I did check the ground bolts/wires, in the area and they are all clean. Funny how this code came up after replacing the air bag module for a code 52. Wonder if the issue is there. Going to try and repair the old module and use it as a test to see. The problem with a Code 24 is that it could come from various different places in addition to the safing sensor (like the crash sensors). Getting a second crash sensor today so maybe I'll look for wiring/connector issues on the old ones in addition to continuity. Might replace them just for grins. This is a tough one to diagnose!!

[sly]

That's why I gave up on mine and suspect the clock spring and/or bag itself for finally killing the system. I had code 24 several times as well. It was random though. And typically only when it was really humid. Then it started blowing the fuse with code 51. After 3 of those (repairing it twice), I gave up. I even modified my module to have an external thermal breaker that I could reset for testing purposes. Just pulled it out of the car and remember that. It's now on my bench collecting dust.

[friskyfrankie]

That's why I gave up on mine and suspect the clock spring and/or bag itself for finally killing the system. I had code 24 several times as well. It was random though. And typically only when it was really humid. Then it started blowing the fuse with code 51. After 3 of those (repairing it twice), I gave up. I even modified my module to have an external thermal breaker that I could reset for testing purposes. Just pulled it out of the car and remember that. It's now on my bench collecting dust.

Yes it can be a difficult thing to fix. Got the second crash sensor today and if they match the part number match the ones already in the car, I'll swap them just to see what happens. Are you saying you deactivated your air bag system? Did you just remove the module? If so, how does the system react? I still wonder if the system gets deactivated with a Code 24 or still works anyway.

[sly]

yeah... pulled the harness out of the module and let them hang. The airbag light will just be on solid when the car is on. I'm still waiting for my bulb to burn out.

I should probably disconnect the airbag itself in the steering wheel so there's no short that causes the thing to pop.

[friskyfrankie]

UPDATE: Received both Crash Sensors and installed them. Completely cleaned the mounting areas and used dielectric grease in the connectors after using contact cleaner. As expected - STILL have the code 24! Well, the old sensors are somewhat crusty (original and a little over 103K miles). Funny how this happened after installing a NOS Air Bag Module. So, either that one is defective or the safer sensor still has an issue. The blue connectors in my above photo CAN'T be the sensor itself. That sensor must be hiding behind the insulation in the kick panel which would necessitate removing the harnesses and the plastic panel they attach to and probably dropping the hood release cable assembly. Will probably try the repaired module first and then resort to removing all that shit in the kick panel! Of course, if the system is still functional, I may just live with it! Just that giving up is not in my nature.....

[sly]

Yes, the sensor is at the end of the wires ducking behind that mess of wires in that body cavity.

[friskyfrankie]

Looks to be a fiberglass or plastic type black covering that sits between the wiring harnesses and the metal kick panel. My guess it the sensor is located behind that black fiberglass/plastic covering. There is a mounting bracket that seems to hold the harnesses to it and probably the hood release cable needs to be dropped for access. Rather a PIA to merely check a sensor but I guess they designed it to avoid accidental damage. Still want to replace the module first but not sure I can release the connectors without removing the module from it's mounting bracket. Still easier than going for the safer sensor so worth a shot. Looks to be next week until the attempt can even be made so we'll see what happens!

[sly]

Now you can see why I gave up. That system is really difficult to get at on a good day.

[friskyfrankie]

Now you can see why I gave up. That system is really difficult to get at on a good day.

Perfectly understandable. I just can't let it go so eventually, I will get to it! If the "new" module or if I get to the safer sensor and it doesn't fix the code, then it's game over!