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bilgladstone

What Happens If I Remove The Passenger Seat?

44 posts in this topic

I may want to temporarily take out the passenger seat. I know I should disconnect the battery and then unplug the SRS wires under the seat, but what happens when I start the car again afterward? I'm thinking that all the airbags get disabled, but does it also affect ABS or traction control or anything else?And once I put it back in, I'll have to pay MB to re-enable the SRS and turn off the warning light, yes?Bil :sun:

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It think so. Usually people only take the seat out during a repair and don't start the car until the seat is back in.

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It will set a code and possibly disable all the airbags if turned on with the airbag disconnected. Only way would be to remove the airbag from the seat and hook it up while secured in a spot that won't cause trouble if it goes off in a crash. IE: Not duct-taped in place as a lumbar support!

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I can accept the risk of driving without airbags. The odds of needing these to be deployed seems to be minuscule. In fact, (as far as I have seen), reports of an errant deployment when just running over a curb, or fail-to-deploy when actually needed (e.g. in an angular impact ), appear to be as frequent as deployed-properly-as-designed. :dunno:

Bil :sun:Running with scissors!

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It's not rocket science, BUT ALWAYS - SAFETY FIRST !

Hi Bil, I've been thinking ... ! :huh: (belive it or not)

In Europe there is/were smart babyseat to buy for m/450, it also had

a electric connection to the babyseat for disabeling airbag/s. The babyseat

was for "nose forward only". Thinking "outofthebox" might lead to an

application for Your purpous ... :rolleyes: - Can a resistor fool the system

that the passenger seat is in it's place ... ?

or

http://www.smart-forum.de/modules.php?op=m...50&forum=24

or

http://www.jhwus.info/page2/page41/page365/page365.html

Yours truly, KfL (still very unhumble)

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KfL, You are always thinking, sometimes even very good thoughts! :)

I have been looking around a little bit on the Internet (does my thinking for me!) and it does appear that a resistor value of 2-3 Ohms will fool the SRS system as you suggest. This is the same a VW, Evo, Prius, Miata, etc, according to the Intertubes. Not sure of power rating (I am not an electronicologist). Can you advise re Watts?

Something like: LINKY or LINKY2

Bil :sun:

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id like to know what its take to fool the air bag system also. i need it for when i got my grandson in the car in his car seat. iv gone threw this before on here an im not about to buy a mb car seat for the few times a year hes in with me. id really like to have that annoying light off

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From my research, and upon advice from others who "should" know, I am pretty sure that all you need is a $5, 2-Ohm resistor like the one above. I might not get around to the summer; maybe you would like to be the "Guinea pig" and go first? :)B :sun:

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Just a thought: I've no idea if this would work, but is there a fuse you can pull that would disable the airbags without setting a code that must be reset?You'd still be "running with scissors", but at least you wouldn't need to pay MB a ridiculous amount to plug in the car and push a button...

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Airbag fuse is also used by ESP. CLICKY So no go.

But if the resistor works, it won't throw a code, so we won't have to go to MB to retrigger the SRS system. Also, the resistor method lets us deactivate just the one seat-back bag and leave all the others active.

Bil :sun:

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It might be easier just to borrow some else's vehicle for the occasion!

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There you go, being all <air quotes> reasonable again! LOL! What fun is that? :P B :sun:

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Please check correct my math if necessary, but wouldn't any 8.8Watt 2.2Ohm resistor will work? I think instead of $4bucks plus shipping you can just go to an electrical supply store and get away with less than a dollar?

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You're right, Izzy. I'll be visiting the electronics shop next trip into town :thumbup:B :sun:

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8.8W is a lot though...the resistor on the ebay page looked quite a bit smaller, more like a 1W or 2W or less. I wonder if there's actually 2amps worth of current through the ABS wires

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1A? 0.5A? I don't have an amp clamp suitable to discover the amperage in that circuit. Is a fuse even necessary? Won't there be a fuse somewhere else in the circuit anyway, or... maybe the airbag unit itself is fused?This fused resistor that tolsen found is the first I've heard of putting a fuse inline with the resistor. Maybe it's not needed but is simply there as a way to make up a device that is easily gripped with fingers to plug in/out? Since it's a "universal" device, maybe other cars need a 2A fuse though ours does not?B :scratch:

Edited by bilgladstone

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The way I read that fused resistor write up, the purpose of the fuse is to quickly blow in the event of an airbag deployment signal, hence allowing the other airbags to correctly deploy. Without the fuse, you might have to wait until the resistor melts down before the other airbags go off. Depends on the individual car's design, of course. The watt rating of the resistor can be much less, as during a normal self-test there would be a far lower voltage than the full 12 it take to set off the bag. Probably a 1/4 watt is adequate, just to be sure find a 1 watt if you can.Anyone reading this be aware that if you put 12 volts across the airbag wires it will go BOOM!

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So you're thinking a 1W 2.2Ω resistor, is that right?B :sun:

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I think 1/4W should be enough too...I've used those for testing traction control ECU before without any problem

Edited by stickman007

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I saw another article that states that a typical test amperage is well under 50 milliamps, deployment amperage around 1. So if test is a full 50 MA across a 2.2 ohm resistance, that means test voltage is .11 volts, or about 0.0055 watts. In other words, 1/4 watt would be fine, which my gut feeling agrees with.Another article said don't test an airbag resistance with an ohmmeter that can put out more than 10 milliamps, again way under 1/4 watt.

Edited by Alex

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