How to install an air bag cut off switch in a
1997 BMW z3.
by Chuck Kamas May 18,2004
First off, BMW does make a kit that includes all instructions and pieces to install this switch. However, this kit is impossible to get. I have seen it. I have held it, then the dealer looked me in the eye and said “I will not sell this to you.” I asked at another local dealer. No. I asked at three other local dealers, either they did not return my phone calls or they said “No”, but more politely.
So, did I give up? NO! Since the dealers would not sell me a kit… I bought it in pieces as replacement parts! Yep, every critical part in the kit has its own released part number associated with it. The parts beginning with 99 0 0 001 XXX are difficult if not impossible to get. That is because the dealer has to ask BMW engineering to release the parts to them and they are usually associated with a specific VIN. Every dealer I talked to, including the Internet based ones, refused to do this. I believe that you can get the paper instructions from the BMW document distribution center http://www.centrallettershop.com If that fails you will have to talk to BMW engineering via the dealer. This is what I did.
So the parts that I ordered are:
On/off switch #61 31 8 381 043
Instructions #99 00 0 001 552 for switch
Wiring cable for production dates before 10/97: #61 10 8 382 216
Instructions #99 00 0 001 555 for cable
--Note: there are many matrixes of parts depending on your build date and trim level (plastic or “wood”). I have just listed the parts that apply to me. Please see instructions #99 00 0 001 552 for a complete list.
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Not desiring to be told no again, I bought my parts at several different dealers. This way no individual dealer is compelled to feel responsible for my safety. Why they would feel responsible for this when they are willing to sell me the actual air bag, a high explosive pyrotechnic device or even brake pads is beyond me! Lawyers!
I only ordered the wiring cable and the switch. I did not order the “wood” panel with cut out… after all it is only wood. Well it turns out that it is worth the $200.00 that BMW charges for it. It is actually a laminate of 1 layer epoxy, 1 veneer of wood, 2 layers of aluminum, 2 layers of fibrous material and 1 layer of plastic to back it all up. Wow! Now that is truly a nice piece of over engineering. I was able to disassemble my center console and cut the hole. It took my buddy and I about four hours one weekend. It turned out pretty good if I do say so myself.
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The actual installation is very straightforward. The goal is to get your car’s electronics to match that of the 1998’s BMW Z3 schematics. Comparing the two in the Bentley manual you can see that the major pieces missing are the switched +12v for the “off” light and the switch itself. The steps are as follows:
1) Disconnect the battery and wait for the caps in the Air Bag Control module to drain. 2) Remove the center console 3) Swap out the panel with the power adapter for the new one with the switch hole. 4) Add the new switched +12v wire, picking up the circuit from behind the drivers kick/speaker panel 5) Interrupt the passenger’s air bag wires with the new switch. 6) Button it all back up. 7) Reconnect the battery. 8) Verify that the airbag light cycles on and then off when turning the ignition switch on. Do this for each position of the air bag cut off switch. Also the “off” light on the switch should illuminate when the cut off switch is in the off position.
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Speaking of the switch. It is quite a nice circuit. It presents to the air bag control module either the passenger air bag squib or a load that emulates it. But it also keeps static electricity out of the system by putting a 100-ohm load across the passenger air bag squib! The emulation load for the controller consists of a ¼ amp fuse in series with a one-ohm resistor. This is to prove that the switch was in the off position during an accident. Lawyers again! |
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As you can see in the tables below, all parts are available as normal order parts. Except for the owners manual supplement which is still just available as a VIN specific special order. The dealers that I talked to would not sell VIN specific special order parts.
REQUIRED PARTS
Z3 roadster produced through 3/98 with plastic console trim panel:
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Plastic trim panel with airbag switch installation opening |
1 ea. |
51 16 8 407 281 |
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Airbag “on-off” switch |
1 ea. |
61 31 8 379 617 |
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Adapter harness “A” (for vehicles produced before 10/97) |
1 ea. |
61 10 8 382 216 |
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Adapter harness “B” (for vehicles produced 10/97 through 3/98) |
1 ea. |
61 12 4 148 707 |
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Owner’s Manual Supplement |
1 ea. |
99 00 0 001 553 |
Z3 roadster produced through 3/98 with wood console trim panel:
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Wood trim panel with airbag switch installation opening |
1 ea. |
51 16 8 407 282 |
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Airbag “on-off” switch |
1 ea. |
61 31 8 381 043 |
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Adapter harness “A” (for vehicles produced before 10/97) |
1 ea. |
61 10 8 382 216 |
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Adapter harness “B” (for vehicles produced 10/97 through 3/98) |
1 ea. |
61 12 4 148 707 |
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Owner’s Manual Supplement |
1 ea. |
99 00 0 001 553 |
Z3 roadster and coupe produced 4/98 through 3/99 with plastic console trim panel:
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Plastic trim panel with airbag switch installation opening |
1 ea. |
51 16 8 407 281 |
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Airbag “on-off” switch |
1 ea. |
61 31 8 379 617 |
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Owner’s Manual Supplement |
1 ea. |
99 00 0 001 553 |
Z3 roadster and coupe produced 4/98 through 3/99 with wood console trim panel:
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Wood trim panel with airbag switch installation opening |
1 ea. |
51 16 8 407 282 |
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Airbag “on-off” switch |
1 ea. |
61 31 8 381 043 |
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Owner’s Manual Supplement |
1 ea. |
99 00 0 001 553 |
Instructions:
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Installation Instructions for Retrofit of BMW Passenger Airbag “On-Off” Switch In Z3 roadster and Z3 coupe vehicles produced through 3/99 (Excluding M roadster and M coupe vehicles) |
P/N 99 00 0 001 552 |
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Supplemental Installation Instructions for Retrofit of BMW Passenger Airbag “On-Off” Switch In Z3 roadster vehicles produced before 10/97 |
P/N 99 00 0 001 555
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Notes:
In Reply to: Air Bags posted by Stuart Brown on August 26, 2001 at 08:15:30:
Anyone know if it's possible to disable the passenger airbag? My wife is expecting a baby and doesn't want to give up her Z3!
SWITCH # L 99 OO O OOL-551 $85,00 PLUS YOUR INSTALLATION ~POLECAT
Please see also- Notes on Installing Pre 10/1997 BMW Z3 Airbag Switch by Jeff a/k/a "Monolith" on the BMW forums March 27, 2012
Esmerelda's Home Page~ Z3ers.com