Nissan 370Z Forum - View Single Post

wstar · 04-22-2013, 02:16 PM

Wow, good progress gomer, be interesting to see if you can fake it out. I have the weight sensor sitting under the pad of the fake Bride seat in my passenger side, but it has never worked correctly, and pretty much always ends up disabling the airbag.

Design Complaint (against Nissan and whoever else does them like this): Based on reading the manual, what I know about how the system works (stock) is this: that sensor module is supposed to look at the pattern of its inputs (I'm not sure if they're just switches, or each one has a variable pressure value) and classify the seat's contents into one of three categories: 1) Nobody/nothing significant in the seat, airbag off 2) Child in seat, airbag off 3) Adult in seat, airbag on. There's only a single status indicator light, which lights up as to say "Hey the passenger airbag is disabled for child safety", which is option (2) above. That status light is off in both conditions 1 and 3. Given that there's some analog real-world variability to the situation (e.g. an adult with their weight distributed strangely at the edges due to body shape or posture), it's a really bad design flaw that the system doesn't tell you the difference between "no airbag because nobody's there" and "airbag on because an adult's sitting there". Hopefully in pristine stock state those two things are so different that it virtually never gets the distinction wrong, but how would you ever know?

And of course, if you're trying to make it work with another seat (and you know, seats are reasonable aftermarket options even just for comfort...), and all you've got to work with is that indicator light, you *really* have no idea whether it's working right just because the light stayed blacked out when an adult sat down, because again that could mean either of two conditions (and either airbag on for adult or off for "not sensing any real passenger").

I really wish there was option for a simple switch for airbag on/off. I get that they want things to be automatic because people will forget the switch, but the whole thing (not just Nissan's design, but the whole way that airbags work and the safety data on them) smells of poor decisions/design when it all gets this complicated on the tradeoffs. At the very least, they could've made the airbag off light also light up when it detect nobody/nothing, and only have the light turn off when it detects an adult and enables the airbag. At least then you'd know for sure what was going on.

I don't care much anymore, personally, because within a few months I'll be stripping out all the airbag system and doing a cage and harnesses anyways :P

04-22-2013, 02:16 PM	#29 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Wow, good progress gomer, be interesting to see if you can fake it out. I have the weight sensor sitting under the pad of the fake Bride seat in my passenger side, but it has never worked correctly, and pretty much always ends up disabling the airbag. Design Complaint (against Nissan and whoever else does them like this): Based on reading the manual, what I know about how the system works (stock) is this: that sensor module is supposed to look at the pattern of its inputs (I'm not sure if they're just switches, or each one has a variable pressure value) and classify the seat's contents into one of three categories: 1) Nobody/nothing significant in the seat, airbag off 2) Child in seat, airbag off 3) Adult in seat, airbag on. There's only a single status indicator light, which lights up as to say "Hey the passenger airbag is disabled for child safety", which is option (2) above. That status light is off in both conditions 1 and 3. Given that there's some analog real-world variability to the situation (e.g. an adult with their weight distributed strangely at the edges due to body shape or posture), it's a really bad design flaw that the system doesn't tell you the difference between "no airbag because nobody's there" and "airbag on because an adult's sitting there". Hopefully in pristine stock state those two things are so different that it virtually never gets the distinction wrong, but how would you ever know? And of course, if you're trying to make it work with another seat (and you know, seats are reasonable aftermarket options even just for comfort...), and all you've got to work with is that indicator light, you really have no idea whether it's working right just because the light stayed blacked out when an adult sat down, because again that could mean either of two conditions (and either airbag on for adult or off for "not sensing any real passenger"). I really wish there was option for a simple switch for airbag on/off. I get that they want things to be automatic because people will forget the switch, but the whole thing (not just Nissan's design, but the whole way that airbags work and the safety data on them) smells of poor decisions/design when it all gets this complicated on the tradeoffs. At the very least, they could've made the airbag off light also light up when it detect nobody/nothing, and only have the light turn off when it detects an adult and enables the airbag. At least then you'd know for sure what was going on. I don't care much anymore, personally, because within a few months I'll be stripping out all the airbag system and doing a cage and harnesses anyways :P __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 04-22-2013 at 02:19 PM.