Air Bag Project
by Scott Fabre
Last Update:
08/03/2005
The symptom was a "INFL REST" indicator light on the DIC. The
code I read out was 16 indicating LH sensor fault.
I fixed the Drivers side Air Bag sensor (SIR) to ground problem
by removing this sensor, cleaning the ground surfaces and applying
dielectric grease.
The following pictures tell the story of how I did this.
Also included are several problems encountered and resolved.
1. Bad battery connectors. (replaced)
2. Bad grounds on accessory lead coming from battery and ground
strap coming from the LT5.
3. Made a workaround to the difficulty of removing the panel with
the gill slits such that next time it will be easy to remove.
4. Added theft protection plate between the gill slits and the
battery.
 This is just the "before" picture.
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 And here we have the tire removed.
Are you getting the impression
I left
out no details :)
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 Using a 10mm for the initial
fasteners (upper left) and then
a
T-30 for the three screws
and a T-15 for the small two
screws.
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 With all fasteners removed the
wheel well rear component can
be
removed.
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 Notice, now the rear wheel well
part is out, the battery hold
down
bolt and battery have been removed
and the lower side cover has
been
lowered. The lower side cover was held in with half dozen small bolts (8mm
head) on the under side and then several T-15 screws on the side.
(accessible by opening the door).
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 This is the last bolt holding the
battery tray. It was a mutha
(technical term for difficult). I
thought it was going to break.
It is easy to see why we have
problems with the sensor and
ground
integrity on the side of
the battery. The sulfuric vapors
and overflow goes into this area.
Lots of signs of corrosion
everywhere in this area. Needles
to say I used some anti-seize
compound on this bolt putting it
back in.
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 Now removing Mr. Sensor.
The rear bolt is 10mm and
the front is
13mm. This I
surmise is not an accident.
The wholes on the tabs (below
pictures) are also of different
sizes in order
to aid in keeping the
sensor facing the right direction.
Otherwise the air bag would only
deploy when you are it from the
rear.
Kind of defeats the purpose.
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 Signs of corrosion on the flange
along with hardened dielectric
grease. (I think) |
 Overexposed picture but you can
see the corrosion and hardened
grease on the right flange. |
 Other grounds (battery ground left
and LT5 ground right) were
also in
need of maintenance. These were
removed, cleaned, greased and reinstalled.
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 Another look at the corrosion. |
 Notice, not only is there paint under
these two ground points
(battery
and LT5 grounds) but look how
thin the metal is that the screws
go into.
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 The threads on these screws are WAY TOO COARSE to be used in such
thin metal. I changed these on final assembly (later) to a fine threaded bolt. The left one has been
cleaned. The right one has not been.
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 I used a very fine grit wheel to
remove the rust and paint from
all the contact areas. Seemed
like the right thing to do.
Seems to me an oversight by
the general to have paint under
these
contact areas.
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 See how shinny? I resurfaced
each on the tabs I found including
ALL of the tabs on the accessory
junction between the battery and
the fire wall.
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 Paint and corrosion removed.
Ready for grease. |
 Better view of all four. Notice
how the sensor mounts have
a
captive nut attached to the
inside of the beam. |
 Shinny, so shinny. All ready to go
back in.
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 Now all greased up.
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 All back in now ready to button
it up.
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 I got side tracked a bit. The battery
lugs needed to be replaced.
I happen to have some laying around. Cost me 55 cents in 1984.
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 I cleaned and applied dielectric
grease to all the tabs on the
accessory lug (shown behind).
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 Accessory lug shown with tabs
removed.
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 Another side track. I placed a protective plate on the inside
against the gill slits to protect the battery from being pierced. This used to be a way of defeating the alarm by the bad
guys as most of you will remember.
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 Notice the reworked slot on
the inside of the panel. I added
this
lug assembly so that I would
no longer have to use the bolt that
fastened from below. The problem
with fastening
from below is that
you have to remove the lower
side piece to get at the bolt.
With this arrangement all I have
to do is remove all other fasteners
the push down and pull out on the
panel to remove it.
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 An even closer look ant eh modification. The protruding part
of
the bolt fits through the whole in the mounting flange. (not shown)
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I also added this rubber tube to the vent
at the top of the battery. The idea is to
vent the vapor away from the car's
electronics.
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