Airbag light is on and sometimes blinks

[sly]

you may have to do all 3 just to make sure.

[alchemist]

so if I remove, sand all three (the damn ones on fenders are in obscure and hard to get at areas) and reinstall and that doesn't fix, will be looking at replacing (junkyard). I see ford part numbers on them, but guessing they are a small fortune.

Another question - does a faulty safing sensor also throw the #9 code?

[sly]

no, that would be code 4.

if that doesn't fix it, you may be wire tracing. Reseating wire harnesses all the way from the sensors to the module (do this with the battery disconnected). If that also doesn't fix it... then yeah... replacement. I'll see if I can find some information on what the resistance is supposed to be of those sensors.

[sly]

looks like it should be around 800-1200 ohm with the sensor unplugged.

[alchemist]

damn. I hope I didn't disturb some wiring around the back of the intake where you have zero room to pull out the stupid PCV breather screen. I was very careful, but remember seeing a lot of vacuum and wiring looms back there.

[pantera77]

Nah, nothing airbag related lives back there.

[alchemist]

Thanks everyone. Will work on the other two sensors tonight (clean grounds, disconnect and reconnect harnesses).

[alchemist]

looks like it should be around 800-1200 ohm with the sensor unplugged.

There's probably only two leads, right? so across the leads, 800-1200 ohms? That way I can find out which one is bad. I did find out that the OEM part number for the entire three box set is F0AB-14B005-AB (superceded to F1AZ-14B004-AB). But when I do a search, those numbers match up with only the left side sensor. But what does ebay know...

[sly]

should only be one actually... the other "lead" is the case that mounts to the car... so the bolt would be a good probe point for the black lead on the multimeter.

[gadget73]

I think one of the changes made with the 1992+ bomb control was to move to two wire sensors. Chassis grounding is less reliable long term as you're finding out.

[alchemist]

So here's the findings:
1. Driver's side crash sensor checks out fine - resistance in spec (1170 ohms)
2. Passenger side crash sensor checks out fine - resistance in spec (1170 ohms)
3. Forward crash sensor (connects to radiator bracket) has infinite resistance.

But here's the deal - the two side crash sensors (in each fender) have two leads at the connector. One is simply a pass through ground. I took readings across terminals and the 'hot' terminal and a mounting bolt. My grounds are very good.

But the center crash sensor has FOUR leads. One is a ground - I was able to figure out that the one with the blue lead coming in (and black lead on the sensor side) is the ground. The ground is just fine (no open circuit), but when I test each of the other three leads across the ground, still get infinite resistance.

So guessing it is the center sensor that is bad here? I can't figure though which lead(s) would really be the live ones and would potentially measure the 800-1200 ohms, would all three?

[sly]

Sounds like the center one is dead. No clue which wire is which though.

[VicCrownVic]

If you don't have the pinout for that sensor by tomorrow night I'll try to remember to post it when I get home and can look through my manuals.

[Mr Bean]

The sensors ground to the body via sensor housing, not the bolt. Make sure there is no rust between the housing and the body. Learned that lesson when I installed sensors on the mod box.

[alchemist]

The sensors ground to the body via sensor housing, not the bolt. Make sure there is no rust between the housing and the body. Learned that lesson when I installed sensors on the mod box.

Yeah, makes sense. That's what I was using. I need a new center sensor.