Removing drivers seat from 2007 towncar

Thread starter #1
Hi,

If I am removing the driver's seat by unscrewing the four nuts on the floor, do I have to deactivate the airbags first, so they don't go off while I'm working? I've read that is a possibility.

Also read that one way to deactivate the airbags is to unplug the battery, leave it unplugged for 15 minutes, then touch the positive and negative cables together to drain any electricity left in the system. Does this sound right--or will I cause a short?

What is the best way to deal with the airbags wile removing the drivers seat?

Thanks!
 
You should de-activate the Supplemental Restraints System (SRS) which includes the airbags and seat belt pretensioners (explosive device at base of seat belt) before doing any work on a feature that includes the SRS or its sensors. It is a safety precaution. The professional way is to plug in a scanner and deactivate the SRS. The Service Manual offers the alternative of removing the negative terminal of the battery and waiting for a short time to allow the capacitors to discharge. I allow 5 mins and this has been a standard practice for many years.

Recently someone mentioned touching the neg cable to the positive cable as you mentioned. We have never done this in the past and I cannot see any reason to do it now. I am not an electrical engineer so I cannot say that it will do any good or harm, but there are keep alive circuits in the electronics for the critical info on mileage, PATS codes, DDM codes, etc. These are unaffected by removing the neg battery terminal, so why would you want "to drain any electricity left in the system" is beyond me.
 
Thread starter #4
Hi,

If I am removing the driver's seat by unscrewing the four nuts on the floor, do I have to deactivate the airbags first, so they don't go off while I'm working? I've read that is a possibility.

Also read that one way to deactivate the airbags is to unplug the battery, leave it unplugged for 15 minutes, then touch the positive and negative cables together to drain any electricity left in the system. Does this sound right--or will I cause a short?

What is the best way to deal with the airbags wile removing the drivers seat?

Thanks!
You should de-activate the Supplemental Restraints System (SRS) which includes the airbags and seat belt pretensioners (explosive device at base of seat belt) before doing any work on a feature that includes the SRS or its sensors. It is a safety precaution. The professional way is to plug in a scanner and deactivate the SRS. The Service Manual offers the alternative of removing the negative terminal of the battery and waiting for a short time to allow the capacitors to discharge. I allow 5 mins and this has been a standard practice for many years.

Recently someone mentioned touching the neg cable to the positive cable as you mentioned. We have never done this in the past and I cannot see any reason to do it now. I am not an electrical engineer so I cannot say that it will do any good or harm, but there are keep alive circuits in the electronics for the critical info on mileage, PATS codes, DDM codes, etc. These are unaffected by removing the neg battery terminal, so why would you want "to drain any electricity left in the system" is beyond me.
--------

Thanks very much!! Do you know what size the floor-bolts are which attach the seat tracks? I've read they may be an atypical metric size....
______________________________
 
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I think the reasoning behind the touching cables is to discharge capacitors at various points in the system, x308 chassis Jag guys for example do it fairly often to get out of assorted limp modes that (I'm told) just leaving the cables unhooked does not accomplish, or at least not in any reasonable timeframe.
I've no reason to believe based on what I've learned and experienced that it is required or useful on a Panther chassis car either. Having the battery disconnected for any length of time (or at all possibly) seems to reset the idle adaptation and 02 sensor trim and such without any special goings on so I'm inclined to think it powers everything down sufficiently inside a few minutes. Also of note it's sort of a pain in the rear to have the aforementioned things reset if all is well and "dialed in" as it should be since it takes some driving/drive cycles to settle it all back in.
 
Thread starter #6
Thanks!

Let's say I unscrewed the bolts, took off the seat, and slid it BACK, further than the factory bolts allow, securing it with custom metal bolt extensions or even wood bracing... Could that set-up cause the air bags to deploy, because the seat is not secured per factory specs? (I am considering this because, due to herniated discs in my back, I sit on pillows, foam and an air mattress to minimize vibration. It works, but I am very cramped in, even with the seat at its farthest level back, and am trying to get more room-- I don't care if rear seats have no leg room....)

Thanks!
 
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The way and how of the seat being bolted down is a safety issue, it needs to stay put as well as factory in an accident.

There may be some issues with airbag deployment strength/speed based on seat position which would then be
erroneous if the seat is artificially closer/further than the position sensor thinks it is. Or that might not apply to this model,
or the drivers side. I'd look into it though, and be aware if there is an accident and insurance gets involved a modification like
that could be used to deny a medical claim if it could be construed as messing with the safety systems of the car.

The attachment method of the seat itself will not cause the bag(s) to blow out of the blue, those are triggered via crash sensors
by a control module. While it's not a bad idea, people tend to be more cautious than they really need to be with airbag stuff.
A lot of it is more that fact that an SRS light will be set if you unplug it while the system is live and require more than a
regular scan tool to reset it than it is a danger of the bag spontaneously blowing. I've handled piles of airbags on shelves, in and
out of cars, shipped them, blown them by the dozens in a metal cage (you can't just throw them away) and I've only ever had one
blow when not intended, and it was after an accident where the electrical system on the car was a mess, and that was a very early
system at that.
 
Thread starter #8
The way and how of the seat being bolted down is a safety issue, it needs to stay put as well as factory in an accident.

There may be some issues with airbag deployment strength/speed based on seat position which would then be
erroneous if the seat is artificially closer/further than the position sensor thinks it is. Or that might not apply to this model,
or the drivers side. I'd look into it though, and be aware if there is an accident and insurance gets involved a modification like
that could be used to deny a medical claim if it could be construed as messing with the safety systems of the car.

The attachment method of the seat itself will not cause the bag(s) to blow out of the blue, those are triggered via crash sensors
by a control module. While it's not a bad idea, people tend to be more cautious than they really need to be with airbag stuff.
A lot of it is more that fact that an SRS light will be set if you unplug it while the system is live and require more than a
regular scan tool to reset it than it is a danger of the bag spontaneously blowing. I've handled piles of airbags on shelves, in and
out of cars, shipped them, blown them by the dozens in a metal cage (you can't just throw them away) and I've only ever had one
blow when not intended, and it was after an accident where the electrical system on the car was a mess, and that was a very early
system at that.
------
THANKS! I very much appreciate the info!
______________________________
 

Town

Senior Member
4,192
89
48
Ottawa Ontario Canada
The seat positioning sensors have nothing to do with the air bag deployment. They are for the DDM to position the seats according to driver selection with memory feature. The DDM provides positioning info to the DSM which moves the seat. Some Town Cars do not have this memory feature and therefore no positioning sensors for the driver seat.

The Lincoln Service Manual advises the SRS must be disabled as a safety measure when working on any part that has an airbag. Other manufacturers than Ford may have different ideas. Familiarity with processes that are not factory service approved but have worked in the past may not apply to inexperienced owners dealing with components for the first time. On a Lincoln you will not notice the effect of the PCM re-learning the idling setting or the transmission shift strategy. The pain is only in the radio resets and the HVAC resets and radio correction. Small price to pay for safety in my opinion.

The only problems with relocating the seat a little farther back is the floor structure and seat belt location in relation to the seat. The floor is reinforced for both the seats and seat belts mounting. The structural integrity of the floor must be retained. The relationship of the seat belt to the seat must be such that the seat belt lap belt fits snugly over the hips/pelvis. If the seat moves back then the belt may be forward of the hips/pelvis and therefore not provide required restraint.
 
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The seat positioning sensors have nothing to do with the air bag deployment. They are for the DDM to position the seats according to driver selection with memory feature. The DDM provides positioning info to the DSM which moves the seat. Some Town Cars do not have this memory feature and therefore no positioning sensors for the driver seat.

The Lincoln Service Manual advises the SRS must be disabled as a safety measure when working on any part that has an airbag. Other manufacturers than Ford may have different ideas. Familiarity with processes that are not factory service approved but have worked in the past may not apply to inexperienced owners dealing with components for the first time. On a Lincoln you will not notice the effect of the PCM re-learning the idling setting or the transmission shift strategy. The pain is only in the radio resets and the HVAC resets and radio correction. Small price to pay for safety in my opinion.

The only problems with relocating the seat a little farther back is the floor structure and seat belt location in relation to the seat. The floor is reinforced for both the seats and seat belts mounting. The structural integrity of the floor must be retained. The relationship of the seat belt to the seat must be such that the seat belt lap belt fits snugly over the hips/pelvis. If the seat moves back then the belt may be forward of the hips/pelvis and therefore not provide required restraint.
Or the seat could rip out of the floor if it's bolted in with weak spacers or adaptors, or into a weaker section of floor.
I've spent 20 years and change working auto salvage and seen more than a few aftermarket or swapped from
another model seat that did not stay where it was supposed to and negated other safety features of the car when it
let the occupant flop around the cabin during an accident. Bad idea unless you are super confident in your work. It can be done, but
one needs to be on top of things. Listen to Town on this one, bad idea unless you absolutely know what you are doing
and can evaluate the seat belt function which I didn't even think of.


I didn't know if the TC is new enough to have positional/weight sensors for the drivers airbag, but many cars do, they don't just blow
at the same time and with the same force/speed for any accident with any seat occupant. I know the passenger side in my 04 has
a weight sensor which was an early attempt to not have a one-size-fits-all airbag (which does not work the best unless you fall into
the design spec for size/weight/position/etc), some of them were a flat cutoff to not deploy if it senses an occupant below a certain weight, they
got smarter as time went on and were able to blow at different speeds/force depending on an educated guess of the passenger size based on weight and seat position.
If it's just a dumb airbag then that's no problem, I'd have thought a car this age with such a good safety rating would have had more going on but
I might be remembering eras of tech wrong.


The idle and fuel trims are absolutely reset/relearned, at least on my 04 and you can verify it with a sufficient scanner as such "adaptations" can be
manually reset without pulling the power using one, and the seat position memory and radio
settings are not wiped, when disconnecting the battery. The 05 and later cars with e-throttle it's even more of a thing.
I had mine off just tonight while replacing
the column shifter tube and just as before, fuel trims back to default state, idle a little odd, cluster data reset, but seat
memory and radio (factory nav) presets and such are not affected. Also the power open/close trunk has to be re-initialized
when power is lost. It's possible the base model radios do not have memory retention but the nav unit does.
 
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