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Discussion Starter #1
HI All,

I searched but could never find a definitive answer for this. I am looking to disable the airbags so I can drive my 4 year old around once in a blue moon. I am aware that this is not really a car for transporting children, but would like to on a very rare occasion or two, in special circumstances.

That being said, I would like to disable the airbags for such a trip. Since I will only do this once or twice, ever, I really do not want to install a switch, as I find them expensive and kind of ugly. I would prefer to remove the fuse instead, and replace it when done. My questions are;

- Has anyone done this successfully
- If done, will the airbag light go off when the fuse is replaced, or is it a trip to the dealer
- As I understand it, the capacitor is meant to power the airbags for 20-30 seconds after power is lost, so I should be OK, but does anyone know different?
- Lastly, which fuse, if any. The manual does not give a fuse for the SRS system, but I assume it must be fused. Looking at the wiring diagrams, it looks unfused?

If it is unfused, time for the switch I guess....


Any thoughts?

Thanks.
 

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I am interested in finding out too, but will just end up installing an airbag switch if there is no other way. I have also been investigating child booster seats that will work. Primarily focused on two that I think may fit. One is the Combi Kobuk (http://www.elitecarseats.com/Combi-Kobuk.pro) and the other is the Recaro Start (http://www.elitecarseats.com/Recaro-Start.pro). Look under the "Specs" tab for both the links above and you will see that the Combi Kobuk is 13.5" wide at the base and the Recaro Start is listed as 13" wide at the base. I have a call in to both manufacturers to confirm this. Both fold and may fit in the boot. The Combi Kobuk has a removable back, so the seat can be used as a booster which would be good for older children.

I too want my children to enjoy the fun of riding in the Elise. I have six children ages 2 months, 2 yrs, 4 yrs, 6 yrs, 8 yrs and 10 yrs old. Obviously the 2 month and 2 yrs olds are too young, but each of the older four would enjoy the special alone time and the experience the Elise provides. I know it isn't as safe as the Excursion they are normally toted around in, but with proper precautions (airbag cutoff, properly fitted child seat, cautioned driving style and driving location), the risks can be mitigated. The passenger side seat belt, once fastened, can be pulled all the way out thus activating the locking retractor, then it can be released back in and snugged up to more securely hold the child/booster.

-Brian
 

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Discussion Starter #3
Not to hijack my own thread, but we have similar tastes. I have a 69 MGB, and a 94 Land Cruiser with factory lockers. Great vehicle for off road excursions into the Nevada desert....
 

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you can't remove a fuse to disable the airbag, even if it had one which it doesn't, it still wouldn't disable it. cutting the wires won't disable it either, twisting them, altering the impedence, nope, its a fail safe device afterall.

needs a proper switch or computer codes
 

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Discussion Starter #5
Thanks for the info, that is what I was starting to suspect as well after reading the diagrams.

Looks like I'l be watching the DIY switch install thread...
 

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You can apply to the NHTSA for an exemption to install an airbag cutoff switch. With the work involved figure $400. I had one on my S2000 and it wasn't ideal as you have to keep switching it on and off. Check this study out- you wont have to dissconnect the airbag for the 8 year old http://www.hsph.harvard.edu/press/releases/press10302000.html

A lot of the fears about airbags are based on the 1st generation airbags not the depowered ones available now.
 

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Proton & Baysailor, Have you guys done anything yet? I too would like to share the fun with my 4 year old son, but there is no way I will let him in the car without a kill switch for the airbag. I wonder will there be any issue on the warranty for installing a on/off switch. Man, it kills me to say no to my little guy every time asked. I wish Lotus will step up and come up with a dealer installed and Lotus approved solution. To me this is a no brainer to ensure the next generation of Lotus supporters.
 

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as charlie noted, you cannot disable srs by cutting power. the capacitors that are used to fire the gas generators can actually hold a charge effectively indefinately. the srs module itself is the only current draw on the capacitors and depending on the system will take varying amounts of time to discharge depending on the system.

the proper way to do this is actually not very difficult at all and can be done quite easily for anyone willing to find the proper components. an airbag cutoff switch does the following when turned: 1. it disconnects the leads to running from the srs module to the gas generator. 2. it shorts the leads to the gas generator together (this prevents accidental deployment due to static discharge or induced currents in the wire) and 3. it places a resistance identical to that of the gas generator ignitor coil across the leads running back to the srs module (which keeps the srs system from setting a fault)

in addition some switches do 4. switch power to a pretty LED that indicates that the switch is set to the disabled state.

the switch itself is a 4PDT+SPST for single stage airbags or a 8PDT+SPST for dual stage bags. the leads running to the airbag are cut and routed to the 4 center poles while the contacts are either wired together for enabled or wired to short or a resistor for enabled. (see attached schematic). the one important aspect of the switch is that it should really be atmospherically sealed in an inert environment.the reason for this is to eliminate the possibility of arcing or stray static discharge across any of the contacts. these types of switches are most commonly used in aerospace and dangerous (gaseous) environments. one common source for these types of switches is to source them as parts from an existing vehicle as some oem vehicle switches use the same principle. there are also a few sites that sell them as well.
 

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Rob, thanks for the description.

I ordered a switch, but have one question about the instructions. To paraphraze...

"Splice this harness to connect the switch. Pink and blue wires go to the airbag. Yellow and white wires go to the airbag computer. It does not matter what wire connects to what on the vehicle. The system is just connecting a loop. As long as one pair of wires is connecting to the airbag and the other pair is connecting to the vehicle you are correctly connecting the airbag switch."

How could this be?
 

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EldersburgElise said:
Rob, thanks for the description.

I ordered a switch, but have one question about the instructions. To paraphraze...

"Splice this harness to connect the switch. Pink and blue wires go to the airbag. Yellow and white wires go to the airbag computer. It does not matter what wire connects to what on the vehicle. The system is just connecting a loop. As long as one pair of wires is connecting to the airbag and the other pair is connecting to the vehicle you are correctly connecting the airbag switch."

How could this be?
technically, its not correct. judging by your description the switch that they sell is basically an interrupt (e.g. it simply disconnects both wires. ) now keep in mind that the switch will work as far as stopping the airbag from deploying BUT... you may not have the protection against accidental deployment. the airbag gas generator coil really needs to be shorted to be sure that it cannot accidentally deploy. keep in mind that the chances of that happening are very small but it is considered important enough that all modern airbag have a shorting clip built into the connector that automatically shorts the pins when you unplug it; this is meant to keep the airbag safe for the small amount of time it might be disconnected during service procedures. i would really recommend that you be sure that any switch that you use does this as well.

if the switch allows you to hook it up either way and it does short the leads then it must short both sides. this would mean that the airbag is safe but the srs side will also be shorted and that risks damaging the srs unit. yet another possibility is that the switch shorts both sides across a resistor. this would mean that the srs unit sees the correct resistance but the airbag would be shorted across a resistor as well. thats safer but not as safe as directly shorting the leads.

you can be sure by testing the switch with an ohmmeter. you place across the leads on one side and then the other, taking note of the resistance each time. a proper switch will read 0 ohms on the airbag side and ~3 ohms on the module side. one final thing to consider is that different airbags have slightly different resistance across the gas generator ignitor coil. 3 ohms is most common but can vary as much as 2-5 ohms. some srs modules will trip the srs light if it sees the resistance across the leads vary too much (an indicator that the ignitor coil might be damaged or defective); usually you want it to be within .5 ohms of the coil. the professional kits come with a set of mil-spec resistors that you pick through to find the best match and then substitute. if this switch does not come with resistors and/or does not short then i would be hesitant to use it.
 

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as charlie noted, you cannot disable srs by cutting power. the capacitors that are used to fire the gas generators can actually hold a charge effectively indefinately. ....

shorts the leads to the gas generator together (this prevents accidental deployment due to static discharge or induced currents in the wire)

Hi

A blast from the past, sorry, but I am thinking about disabling the passenger airbag semi-permanently, (without using a key switch).

My query is - if I pull the plug from SRS and then short the leads to airbag, will this prevent it from firing (i.e. by discharging the caps)?

Thank you
 
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