1991 p72

[sly]

count how many times it's flashing. there's a posting somewhere on here of the one digit codes for the 90-91/92 airbag systems.

as for the steering fluid flush... send the return line into a catch pan and have someone crank it and turn the wheel lock to lock a couple of times and then kill it while more fluid is fed into it (about a quart every 2-3 seconds). If the fluid isn't flushed out all the way, hit it again. You may need to replace the return line as getting it off the reservoir if it's original will be impossible without cutting it or breaking the tank.

[sly]

found the post with the air bag codes... http://www.grandmarq.net/vb/showthre...l=1#post553578

Those are engine codes. Airbag codes are one of two different code lists. 92 ought to have 2 digit codes:

| Code | Description | Pinpoint Test |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| No Indicator | Inoperative air bag indicator circuit | A |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| Continuous Indicator | Diagnostic monitor disconnected or inoperative | B |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 12 | Loss of battery power to air bag firing circuit | C |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 13 | Front crash sensor or air bag circuit shorted to ground | D |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 21 | LH B-Pillar safing sensor not mounted to vehicle properly | E |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 22 | Safing sensor shorted or stuck closed | F |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 23 | Open connection in safing sensor feed circuit | G |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 24 | Safing sensor diagnostic circuit open | H |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 31 | All system air bag(s) open | I |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 32 | High resistance or open circuit in driver air bag circuit | J |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 33 | High resistance or open circuit in passenger air bag circuit | K |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 34 | Low resistance in driver air bag circuit | L |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 41 | Open connection in forward crash sensor circuit | M |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 44 | RH front crash sensor not mounted to vehicle properly | N |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 45 | Center front sensor not mounted to vehicle properly | O |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 46 | LH front crash sensor not mounted to vehicle properly | P |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 51 | Diagnostic monitor internal thermal fuse open | Q |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 52 | Backup power supply fault | R |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 53 | Diagnostic monitor internal fault | S |
|-----------------------+-----------------------------------------------------------------+-----------------------|
| 99(1) | All crash sensors disconnected | T |
|-----------------------+-----------------------------------------------------------------+-----------------------+



If yours is single digit codes:

Code Component/Fault Description
No Air Bag Indicator - Inoperative Indicator Circuit
2 All Primary Crash Sensor 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- High Resistance or Open
7 Passenger Side Air Bag Circuit - High Resistance or Open
8 Primary Crash Sensor Circuit - 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

from http://www.veryuseful.com/mustang/tech/airBag/

[IPreferDIY]

I'm not sure if or how well my power steering fluid method would work for a 1991, but I put the front end on jack stands, put a sleeve over the return line and into a container, cap the inlet on the reservoir, and move the steering wheel back and forth without starting the engine while adding fresh fluid. That's been good enough to get the old fluid out while taking the fresh fluid in.

How exactly does heat work on rusty stuff, especially bolts? I'm aware of it being done but have never done it myself. I wish it had come to mind in 2014 before taking a BFH to my exhaust flange bolts to get them out. I'll be sure to have a torch on standby if/when I do my O2 sensors.

[Mr Bean]

Good info, thanks. Looks like I am getting code 10. Great, a short that I gotta trace. Mothereffer.

Oh and I think my climate control is also fubar. The lever that moves from hot to cold is kinda lose and it feels like something inside is gonna snap if I move it left or right.

As far as heat, it causes metal to expand, witchcraft happens and stuff magically comes apart. Or something like that.

[VicCrownVic]

Here's another thread with airbag related info:
http://www.grandmarq.net/vb/showthre...ghlight=Airbag
There are a couple of posts with some info I scanned from my '91 EVTM/Service Manual.

[sly]

the bolt will expand less than the nut typically and break stuff loose. If into heavier metal like a frame, the frame nut expands differently than the bolt. yadda yadda. gets things moving so penetrating lube can get in and help things move more easier and stuff. Thermodynamics and stuff.

[sly]

Good info, thanks. Looks like I am getting code 10. Great, a short that I gotta trace. Mothereffer.

It may have been an intermittant thing due to water or probing with an old style test light. You will need to replace the thermal fuse in the air bag module (looks like a tiny bullet with a wire coming out both ends inside a plastic case (half black and half white). The point direction supposedly matters, but the thermal fuse doesn't work like a diode, so I don't see why it would matter any. Or just replace the module with one from a yard once you ensure there's no shorts in the system like I did with my 93. Though you'll be limited to 90/91 models with the optional airbag and maybe 92 MGM/CV. Not sure exactly when they stopped using that module and I'm not sure the newer module would work. I do have one spare that would work in my 93 (repaired my original one and tested it). If we find out that they're compatible, that could be an option.

[HiFiMerc]

Witchcraft is the more likely explanation. On a related note, I finally found the other two airbag sensors on 90-91. Behind the kick panels. Don't know how I've missed them all these years.

[pantera77]

Oh and I think my climate control is also fubar. The lever that moves from hot to cold is kinda lose and it feels like something inside is gonna snap if I move it left or right.

All the 90-94 climate control heads do that. Even if you find one that isn't broke it sure as shit will be in the future. Be gentle and it will last.

You replaced the PVC grommet and screen as well right?

[Mr Bean]

All the 90-94 climate control heads do that. Even if you find one that isn't broke it sure as shit will be in the future. Be gentle and it will last.

You replaced the PVC grommet and screen as well right?

What actually breaks inside the climate control? Is that something that can be taken apart and fixed?

10-4 on the screen.

[sly]

Oh and I think my climate control is also fubar. The lever that moves from hot to cold is kinda lose and it feels like something inside is gonna snap if I move it left or right.

All the 90-94 climate control heads do that. Even if you find one that isn't broke it sure as shit will be in the future. Be gentle and it will last.

+1 Also, http://www.grandmarq.net/vb/showthre...ck-manual-HVAC

[VicCrownVic]

What actually breaks inside the climate control? Is that something that can be taken apart and fixed?

10-4 on the screen.

There are plastic spacers (not sure if that's the best way to describe it) that keep the lever from flopping all over. Once they break the chrome rectangular knob is all that keeps the lever from swiveling back into the face plate. The lever with the chrome knobs is 1 inch or shorter and it is connected to a longer arm that moves the heat or mode selection. The pivot connection between the knob lever and the internal arm is all metal so when the plastic spacers are gone there really isn't anything more that is likely to break.

I have a spare ATC control unit from a '91 that I took apart to see what causes the sloppiness, I'll have to remember to get some pics since I'm not sure I can give a very good explanation. Basically the face plate is attached to the chassis by plastic welds (just melted together) so I don't know how well putting it back together would go even if you could fab up some spacers to keep the knob lever from flopping around.

Does this P72 of yours have ATC or Manual Controls?

[Mr Bean]

There are plastic spacers (not sure if that's the best way to describe it) that keep the lever from flopping all over. Once they break the chrome rectangular knob is all that keeps the lever from swiveling back into the face plate. The lever with the chrome knobs is 1 inch or shorter and it is connected to a longer arm that moves the heat or mode selection. The pivot connection between the knob lever and the internal arm is all metal so when the plastic spacers are gone there really isn't anything more that is likely to break.

I have a spare ATC control unit from a '91 that I took apart to see what causes the sloppiness, I'll have to remember to get some pics since I'm not sure I can give a very good explanation. Basically the face plate is attached to the chassis by plastic welds (just melted together) so I don't know how well putting it back together would go even if you could fab up some spacers to keep the knob lever from flopping around.

Does this P72 of yours have ATC or Manual Controls?

Alright, I'll take a look. I wonder if I can fab up a brass spacer of some sort to eliminate the issue. I am not sure if it have ATC or manual controls. How do I tell? It has 2 levers one above the other. Seeing how this car is stripped of just about all options I am leaning towards manual.

[VicCrownVic]

The 2 levers for temperature range and mode (A/C, Vent, Defrost, etc.), both prone to sloppiness, should be identical to the ATC unit.
It's the third one (vertical, on the left, not prone to failure afaik) for blower speed control that will tell you if it's ATC. It has a setting that says Auto if it is ATC.
Your reasoning makes sense and I would also be a bit surprised if it does have ATC.

ATC unit:

[Mainemantom]

That 90-91 Ac/ATC controller is a poor design. Those spacers need lube that will not eat plastic. The controller needs to be gently moved so the spacers do not break. That is how I broke mine, in a hurry, on a cold night. If you have the manual controller, I have the part number from the nos one I have. Let me know if you want the number. I will have to do some digging.