For the Electrical Geniuses - Aftermarket Seats and Airbags
10-31-2005, 05:17 PM
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For the Electrical Geniuses - Aftermarket Seats and Airbags
I just read with some terror that the passenger airbag in the dashboard is one of those "smart" airbags that only activates when someone is sitting in the passenger seat. This brings up a couple of questions, since I have already bought Sparco front seats and had my rear seats reupholstered to match, and planned to install them very soon. However, I still drive the car regularly with passengers in it, and am not willing to give up the dash airbag in addition to the airbag that was in the stock seat. Now, the questions -
1. Can anyone confirm this for me? I am currently away from home and my shop manual, and will be for a month. It seems strange to me, because most of the cars I've seen with "smart" airbags have a special light to tell you when the passenger airbag is not armed.
2. If it is in fact a "smart" airbag, once I disconnect the stock seat completely, do any of you electrical geniuses think that there would be a way to fool the car into thinking that someone was sitting in the now nonexistent passenger seat and leave the airbag on all the time?
3. I know that once I take the seats out, the airbag light will be on all the time because the seat airbags will be missing. Do you think there would be a way to again fool the car into thinking they were still there and operating normally so that if the airbag light came on I would know there was a problem with the remaining fuctioning airbags? Or, is there a way to pull codes like you can with a CANSCAN for CELs so that I can check often to make sure all is well?
Thanks in advance for any help.
1. Can anyone confirm this for me? I am currently away from home and my shop manual, and will be for a month. It seems strange to me, because most of the cars I've seen with "smart" airbags have a special light to tell you when the passenger airbag is not armed.
2. If it is in fact a "smart" airbag, once I disconnect the stock seat completely, do any of you electrical geniuses think that there would be a way to fool the car into thinking that someone was sitting in the now nonexistent passenger seat and leave the airbag on all the time?
3. I know that once I take the seats out, the airbag light will be on all the time because the seat airbags will be missing. Do you think there would be a way to again fool the car into thinking they were still there and operating normally so that if the airbag light came on I would know there was a problem with the remaining fuctioning airbags? Or, is there a way to pull codes like you can with a CANSCAN for CELs so that I can check often to make sure all is well?
Thanks in advance for any help.
Last edited by ScudRunner; 10-31-2005 at 05:36 PM.
10-31-2005, 06:16 PM
#2
the only thing i can think of for "fooling" the car into thinking the passenger seat is occupied is by finding out the resistance of the circuit for when the seat is "occupied". it's called a smart airbag system because of the passenger seat occupany detector. (i think this car has one) the same with the side airbag, you have to find the resistance of that circuit and find some sort of resistor to fill in that gap.
hope that made sense...cause i think i confused myself too.
hope that made sense...cause i think i confused myself too.
11-02-2005, 01:54 PM
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So, I did get Mazda to answer that no, the 04 RX-8 does not have a weight sensor in the passenger seat. So, the airbag is armed all the time. They would not, however, answer the question of whether removing the stock seats would affect the functioning of the remaining airbags in the system (front and curtain). I can't blame them, because they have to take the lawsuit-proof stance of "don't remove the stock seats."
Last edited by ScudRunner; 11-02-2005 at 03:19 PM.
11-02-2005, 04:49 PM
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Shifty Bastard.
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Airbag 101:
There are buckle switches, but these are only used to effect during frontal collisions. If a front seatbelt is unbuckled at impact then the threshold for the second stage charge is lowered. The front airbags fire at one of two rates. If the impact is "hard" then two inflators deploy the airbag and it comes out at a greater rate. "Softer" frontal impacts will only fire one inflator. If the belt is unbuckled, then the second inflator will fire at a lesser frontal impact speed (ie, the bag will come out hard during a low speed collision) therefore protecting the idiot who was too stupid to protect himself.
This will happen whether the seat was occupied or not. There is a modifier to what I have stated above, though. The RX-8 also has seat position sensors. If the seat if in a forward position (ie, the driver has short legs and is close to the wheel) then the airbag only fires one inflator.
Gomez.
There are buckle switches, but these are only used to effect during frontal collisions. If a front seatbelt is unbuckled at impact then the threshold for the second stage charge is lowered. The front airbags fire at one of two rates. If the impact is "hard" then two inflators deploy the airbag and it comes out at a greater rate. "Softer" frontal impacts will only fire one inflator. If the belt is unbuckled, then the second inflator will fire at a lesser frontal impact speed (ie, the bag will come out hard during a low speed collision) therefore protecting the idiot who was too stupid to protect himself.
This will happen whether the seat was occupied or not. There is a modifier to what I have stated above, though. The RX-8 also has seat position sensors. If the seat if in a forward position (ie, the driver has short legs and is close to the wheel) then the airbag only fires one inflator.
Gomez.
11-02-2005, 05:07 PM
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Gomez,
Thanks. What I can't find written down anywhere is whether or not the front airbags will function at all if the seat track sensors are removed (as I imagine they would be in a seat replacement issue). It would appear that I could wire a resistor into the wiring harness for the side airbag sensors to keep the airbag module from freaking out, but the seat track sensors are now the sticking point.
Thanks. What I can't find written down anywhere is whether or not the front airbags will function at all if the seat track sensors are removed (as I imagine they would be in a seat replacement issue). It would appear that I could wire a resistor into the wiring harness for the side airbag sensors to keep the airbag module from freaking out, but the seat track sensors are now the sticking point.
11-02-2005, 05:42 PM
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The seat track sensors are a Hall element magnetic sensor. They operate by producing a electrical signal dependant on the amount of magnetic flux coupling that occurs when the seat is either over the metal target, or away from it. The electrical signal is sent to the airbag control module.
Without looking at the seats....I imagine you could hook up this arrangement to your new seats and seat tracks. Even if you tie wrapped the sensor to the underside of your new seat and had no target fitted....your airbags would still fire. They would just fire both inflators...ie, the airbag module is sensing you are not near the forward target, so it fires at the full rate.
Gomez.
Without looking at the seats....I imagine you could hook up this arrangement to your new seats and seat tracks. Even if you tie wrapped the sensor to the underside of your new seat and had no target fitted....your airbags would still fire. They would just fire both inflators...ie, the airbag module is sensing you are not near the forward target, so it fires at the full rate.
Gomez.
11-02-2005, 05:45 PM
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And since I am imparting this advice to an American, I add my standard disclaimer that you follow this course of action at your own risk.
I accept no responsibility for your dumb ***....
I accept no responsibility for your dumb ***....
11-02-2005, 07:40 PM
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Originally Posted by Gomez
They would just fire both inflators...ie, the airbag module is sensing you are not near the forward target, so it fires at the full rate.
Gomez.
Gomez.
Guess I'll have to wait until I get home and take a look at the seats.
11-14-2005, 05:30 PM
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If anyone is curious, the resistance range that the airbag control module is looking for from the side airbag module is 1.4-3.2 ohms. I have decided to go with a 1/2W 2.0 Ohm resistor, based on some other research that I have done. I will update whether or not what I do works as soon as I get home from my trip to NM. Also, here's what 350Z guys have available to them, those lucky punks.
Air Bag Connector
Air Bag Connector
11-14-2005, 05:46 PM
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Originally Posted by ScudRunner
here's what 350Z guys have available to them, those lucky punks.
________
Best vaporizer under 300
Last edited by PUR NRG; 05-01-2011 at 07:13 AM.
11-14-2005, 07:05 PM
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True, but there is the added benefit of "knowing" it will work, since Nissan made it. I'm still not convinced I'll be able to do this right, or that I have made all the right deductions.
11-15-2005, 12:16 PM
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The 1.4-3.2 ohms value came right out of the shop manual list of possible codes associated with the airbag light. I chose 2 ohms because that is the value that the shop manual has you use to do any tests on the airbag itself.
Last edited by ScudRunner; 11-15-2005 at 12:59 PM.
11-18-2005, 11:15 PM
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Success! Just got done attaching the resistor to the airbag harness, reattached the battery, and turned the key to ON. Airbag light came on, and went out after a few seconds, just like it should. Seems to have worked like a charm.
One note, however. I have a power driver's seat. In order to get the seatbelt connector and seatbelt switch (part of the SRS system) off so that I could put them on the new seat, I pretty much had to take the entire seat apart and pull out the whole wiring harness. That sucked ***, wasn't easy to do, and the seat didn't really go back together that well (the shop manual would lead one to believe the seat just comes apart; I did not find that to be the case at all). I had planned to sell these seats to someone, but without the wiring harness, I imagine a power seat to be fairly worthless unless you just happen to like riding around in the exact positiont the seat was in before I took it out. Oh well. At least the resistor thing worked.
One note, however. I have a power driver's seat. In order to get the seatbelt connector and seatbelt switch (part of the SRS system) off so that I could put them on the new seat, I pretty much had to take the entire seat apart and pull out the whole wiring harness. That sucked ***, wasn't easy to do, and the seat didn't really go back together that well (the shop manual would lead one to believe the seat just comes apart; I did not find that to be the case at all). I had planned to sell these seats to someone, but without the wiring harness, I imagine a power seat to be fairly worthless unless you just happen to like riding around in the exact positiont the seat was in before I took it out. Oh well. At least the resistor thing worked.
10-26-2007, 04:41 PM
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i see you used 2.0 ohm, i went to radio shack and the salesperson told me you probably meant 2k ohm. is he right, or do you mean 2.0? 2 ohm is a very low resistance, but from what i know there shouldnt be alot of resistance in an airbag circuit.
10-26-2007, 04:55 PM
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10-27-2007, 01:40 AM
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all i'm asking for is what the resistance range for the seat airbag should be. i don't have a digital multimeter only analog.
and what harm is there in asking? the worst-cased scenario if he tells me the wrong resistance for some reason is that the light will stay on. i already have that. so i don't see a problem.
and what harm is there in asking? the worst-cased scenario if he tells me the wrong resistance for some reason is that the light will stay on. i already have that. so i don't see a problem.
10-27-2007, 09:04 AM
#24
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My point about RadioShackGeeks is that he had NO IDEA what you needed, but was more than willing to give you advice that was, literally, 1000% wrong.
ScudRunner posted the right range of values (1.4 to 3.2 Ω) and even gave a good average (2.0 Ω) and a wattage/size (1/2 watt).....the RSG's "suggestion" of 2k is a thousand times more resistance. (so he is actually 100,000% wrong, right?)
S
ScudRunner posted the right range of values (1.4 to 3.2 Ω) and even gave a good average (2.0 Ω) and a wattage/size (1/2 watt).....the RSG's "suggestion" of 2k is a thousand times more resistance. (so he is actually 100,000% wrong, right?)
S
10-27-2007, 12:26 PM
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oh i misunderstood you. i thought you were telling me not to accept ScudRunner's advice. i'm sorry. I totally agree with not trusting radio shack on anything more complicated than "how much is this cell phone cover?" I worked at one a few years ago and had NO prior electronics experience. i figured they hadn't changed policy hahahah.