91 Grand Marq air bag light

[01Townie]

hey guys, so my brother is looking at buying a 91 grand marq and the air bag light is flashing. he said he looked it up and said that there was some problem with a coil in the seat belt somewhere that may be bad or the wiring in the buckle. can anyone enlighten me on what the issue could be or confirm his theory? im goin to hook it up to my OBD1 reader tomorrow to see if itll read the code if there is one but I wanted one of yall's opinions first to see if yall know anything about it.

[chitownvic]

A lot of the times the Air Bag sensor up front goes bad from age along with moisture etc etc.. It's a common problem on the air bag cars.. There's a fix for if on here somewhere.. I'm sure somebody that knows more will chime in


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[HiFiMerc]

Your OBD reader won't show any airbag codes. Different systems.

The air bag light will blink out the code. And you;re thinking, oh, I'll just pull the bulb out, No, don't go pulling the bulb, it will just get angry at you and beep out the code with a rather annoying beeper.

[01Townie]

Your OBD reader won't show any airbag codes. Different systems.

The air bag light will blink out the code. And you;re thinking, oh, I'll just pull the bulb out, No, don't go pulling the bulb, it will just get angry at you and beep out the code with a rather annoying beeper.

yeah, I just looked at it, but I didn't look to see what it was blinking. I forgot that's how they worked, haven't worked on a box in a while. ill have to see what the code is later.

[sxcpotatoes]

Probably clockspring in the steering wheel under the bomb/horn pad. Since you said coil, that's what springs to mind.

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[01Townie]

i checked the light...it flashes 8 times over and over....any ideas?

[HiFiMerc]

Copy and pasted from Panterra's post.

Is your airbag light on in your 90/91 Box? Then here's a good place to start. The light will flash the code, so get ready to count!

2 - All Primary Crash Sensors Disconnected.
3 - Air Bag Deployment Circuit - Low Battery Voltage or Low Backup Power Supply Voltage
4 - Safing Sensor - Diagnostic Circuit Open or Low Primary Crash Sensor Resistance
5 - Air Bag Circuit or Crash Sensor Circuit - Shorted to Ground
6 - Driver-Side Air Bag Circuit - Open or High Resistance
7 - Passenger-Side Air Bag Circuit - Open or High Resistance
8 - Primary Crash Sensor - Not Mounted to Vehicle Properly
9 - Primary Crash Sensor Circuit - Open or High Resistance
10 - Diagnostic Monitor Internal Thermal Fuse - Open Due to Intermittent Short to Ground

Also, note that you can't just pull the bulb to get rid of that annoying light. The Airbag module checks resistance across the Airbag light circuit, and removing the bulb makes it beep endlessly.

[01Townie]

Copy and pasted from Panterra's post.

Is your airbag light on in your 90/91 Box? Then here's a good place to start. The light will flash the code, so get ready to count!

2 - All Primary Crash Sensors Disconnected.
3 - Air Bag Deployment Circuit - Low Battery Voltage or Low Backup Power Supply Voltage
4 - Safing Sensor - Diagnostic Circuit Open or Low Primary Crash Sensor Resistance
5 - Air Bag Circuit or Crash Sensor Circuit - Shorted to Ground
6 - Driver-Side Air Bag Circuit - Open or High Resistance
7 - Passenger-Side Air Bag Circuit - Open or High Resistance
8 - Primary Crash Sensor - Not Mounted to Vehicle Properly
9 - Primary Crash Sensor Circuit - Open or High Resistance
10 - Diagnostic Monitor Internal Thermal Fuse - Open Due to Intermittent Short to Ground

Also, note that you can't just pull the bulb to get rid of that annoying light. The Airbag module checks resistance across the Airbag light circuit, and removing the bulb makes it beep endlessly.

thanks man! i found the crash sensor...just dont know what it means my not mounted pro[erly...do you know what that means exactly?

[HiFiMerc]

Bad ground maybe. It probably grounds through the mounting screw (it's a green screw, I assume it's a ground.) Take it off (unhook the battery first and leave it alone for a few minutes when working with air bag stuff, better safe than sorry) and clean up the mounting points.

[01Townie]

Bad ground maybe. It probably grounds through the mounting screw (it's a green screw, I assume it's a ground.) Take it off (unhook the battery first and leave it alone for a few minutes when working with air bag stuff, better safe than sorry) and clean up the mounting points.

i cleaned everything up and hooked the battery back up but the light is still flashing...any other ideas?

[HiFiMerc]

Put a piece of black tape over the light.

It probably still works. Every time I see a 90/91 in a junkyard with medium to severe front end damage, the air bag is deployed.

[sly]

check the wires going to it. any harness may need cleaning/greasing (dielectric).

[HiFiMerc]

The one behind the grill of my dad's 91 was corroded so bad, that it had split open. Turns out, that wasn't the one throwing a code.

[01Townie]

He ordered a new sensor, but I'm gonna do the black tape option anyway just in case it don't work. That's the only reason it's not passing inspection and he wants it on the road so that's what I'm gonna do. Anyone know how to pull the gauge cluster out? Never done it on a box before

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[kishy]

I just did this on my '91 (different code, my clockspring is broken).

What I did, in summary, since the clockspring is one expensive mofo:

• Removed airbag redundant power supply. It's a big capacitor in a blue plastic housing that hides beside your ECU. Accessible if you put your head under the dash. Plastic piece above the pedal needs to go in order to access it. **THIS THING is why people say to wait after you disconnect the battery. It holds power (as capacitors do) to detonate the airbag in the event the primary power source is interrupted.
• Removed airbag diagnostic module. It's a blue plastic housing near the warning chime, to the left of the radio. Same as above for accessibility.
• Disconnected the airbag itself and taped off its connection to try to ensure no unexplainable weird incident causes a bomb to go off in my face.
• Discovered that Ford actually implemented THREE-TIER warning systems on these cars. E.g. If you have a problem, the light flashes. If the light has a problem, the beeper beeps. Well, if you remove the beeper but not the light, the light stays on solid. So I removed the bulb.

To remove the cluster is really easy. It's also really annoying.
Note that you do NOT need to disconnect the shifter position indicator (PRNOD1) to just get this light bulb, but it is a necessary step to fully remove the cluster. That is done from underneath the steering column.

1. Disconnect battery.
2. If you feel so inclined: do the stuff I said above.
3. Have wheel chocks handy if your parking brake is not trustworthy.
4. Remove the trim pieces at the left and right sides of the column (aluminum fake woodgrain wrapped around plastic).
5. Remove the headlight knob. Not as easy as it sounds. Pull the switch out to the 'on' position, twist knob around until you can see the small metal latch that holds it on the shaft by friction. Use pliers to hold the shaft and a skinny screwdriver or allen wrench to push on the little latch while pulling on the knob. You'll figure it out. Don't just yank on the knob, you may destroy your headlight switch. Once main knob is off, pull off autolamp dial.
6. Locate and remove the T-20 Torx screws from the trim piece that holds on the trim that goes around the cluster, HVAC, clock etc. There are some along the top edge and some that were hidden under the trim you already removed.
7. Put key to unlocked position, pull shifter down to 1. This is where your wheel chocks or parking brake comes into the picture.
8. Carefully pull the trim around the cluster, hvac, etc out. There is a small rubber hose for the driver side window defog. You have to release it for the trim to come out. The hose is held on with "barbs" on the hard plastic nozzle part, you can use the end of a screwdriver to push one of them in and it will release. You'll see what I mean when you see it.
9. Possibly requires adjusting column angle: remove trim once hose is undone.
10. Remove cluster screws. There are 4 of them, also T-20 Torx.
11. You can now pivot the cluster around enough to access the airbag bulb. You'll be doing it half blindly because, between the harness connectors and the shift indicator cable, you can't pull it out enough to fully turn it around. If you cannot get the bulb holder out then you'll want to undo that shift indicator cable.
12. If that is necessary - remove the 5 bolts that hold in the panel under the column (3 along the top recessed in holes, and 2 at the bottom), remove that panel. Study how the cable mechanism works. Carefully unhook it from the shift lever (lever has to be down in 1 to do this), and then spin the adjustment plastic wheel until it threads out and is disconnected. Note for the future: this is how you adjust the position of the pointer.

Assembly is reverse of disassembly...