DIY: [How-To:] Racing Seat airbag light fix

omm370z · 01-26-2013, 11:44 AM

Quote:

Originally Posted by dansracing

Mike I can get mine to turn off by moving it around under the cushion. I found that it works best if it is positioned way back in the seat where the passenger is sitting on the front 1/3 of the sensor pad.

The reason it works in the OEM seats is because it sits on 2" of foam and is fastened to the wire rim around the cushion pad. The sensor acts like a small hammock for your but. That tension activates it. In our racing seats, the hard bottom doesn't allow any stretching of the sensor pad so its hard for it to register unless it is in just the right position.

If the racing seats do not have removable cushions you can always put the sensor pad under it to turn off lights, but you will never have airbag activation in that seat during a collision.

Wait...are you saying that we are fooling our selfs with this? So even with the light off and the whole thing done right there will be no activation when we get a collision??

gomer_110 · 03-03-2013, 12:51 AM

A couple things I noticed when I was installing my Bride Vios III:

If your anal retentive like me and verify the 4.7 Ohms after it's soldered in place and don't be alarmed when it reads <1 ohm. There's something with the plug that makes it show up this way (wasted 2 resistors because of this).

Looking at the weight sensor pad it looks like a glorified strain gauge (as it stretches it increases resistance). The problem is the module attached to it. I would say with some certainty that if someone was to measure resistance on the traces at the pad to module connection that we'd be able to solve this whole weight sensor issue once and for all. Unfortunately I don't have the kind on money laying around to risk damaging mine. Now if someone wants to give me one to test this with then let me know (can't guarantee it'll come back in one piece though).

Mr&Mrs · 03-03-2013, 07:12 AM

If you were 100% on being able to have an always on plug or something by doing this I may donate mine for the cause. I do not want to go thru all this trouble to still have a non working airbag for my wife! Next week the seats go back in so if I have problems I will send it your way if you think an always on option can be made.

Quote:

Originally Posted by gomer_110

A couple things I noticed when I was installing my Bride Vios III:

If your anal retentive like me and verify the 4.7 Ohms after it's soldered in place and don't be alarmed when it reads <1 ohm. There's something with the plug that makes it show up this way (wasted 2 resistors because of this).

Looking at the weight sensor pad it looks like a glorified strain gauge (as it stretches it increases resistance). The problem is the module attached to it. I would say with some certainty that if someone was to measure resistance on the traces at the pad to module connection that we'd be able to solve this whole weight sensor issue once and for all. Unfortunately I don't have the kind on money laying around to risk damaging mine. Now if someone wants to give me one to test this with then let me know (can't guarantee it'll come back in one piece though).

WhiskeyHotel · 03-03-2013, 08:18 AM

Quote:

Originally Posted by gomer_110

If your anal retentive like me and verify the 4.7 Ohms after it's soldered in place and don't be alarmed when it reads <1 ohm.

For this to happen, the 4.7 Ohm resistor would have to be in parallel with another resistance that's about the Ohm value you are reading on your meter.

SouthArk370Z · 03-03-2013, 08:35 AM

Quote:

Originally Posted by WhiskeyHotel

For this to happen, the 4.7 Ohm resistor would have to be in parallel with another resistance that's about the Ohm value you are reading on your meter.

If the resistor was connected to the controller when the measurement was taken, there will be "sensing voltage" and/or general solid-state leakage present that can throw off the meter.

WhiskeyHotel · 03-03-2013, 08:57 AM

Yeah, it would depend on where it was measured and whether it was connected or not.

gomer_110 · 03-03-2013, 10:37 AM

Quote:

Originally Posted by WhiskeyHotel

For this to happen, the 4.7 Ohm resistor would have to be in parallel with another resistance that's about the Ohm value you are reading on your meter.

Quote:

Originally Posted by SouthArk370Z

If the resistor was connected to the controller when the measurement was taken, there will be "sensing voltage" and/or general solid-state leakage present that can throw off the meter.

Quote:

Originally Posted by WhiskeyHotel

Yeah, it would depend on where it was measured and whether it was connected or not.

The measurement was taken with the connector off the car. It was done with the resistor in place and without it.

This is what I had inside working with. (not my picture but close enough)

Wasn't trying to start a argument just trying to point out a nuance of doing this DIY.

gomer_110 · 03-03-2013, 10:52 AM

Quote:

Originally Posted by Mr&Mrs

If you were 100% on being able to have an always on plug or something by doing this I may donate mine for the cause. I do not want to go thru all this trouble to still have a non working airbag for my wife! Next week the seats go back in so if I have problems I will send it your way if you think an always on option can be made.

Yeah I wouldn't feel comfortable taking your's unless I knew I could actually make it work. Think I just need to find one off a Z that's been totaled and sitting in the salvage yard.

SouthArk370Z · 03-03-2013, 01:51 PM

Quote:

Originally Posted by gomer_110

Wasn't trying to start a argument just trying to point out a nuance of doing this DIY.

Not arguing (at least I wasn't). Just throwing around some ideas, trying to figure out why you're not reading 4.7 ohms.

sixpax · 03-03-2013, 02:32 PM

Quote:

Originally Posted by gomer_110

A couple things I noticed when I was installing my Bride Vios III:

If your anal retentive like me and verify the 4.7 Ohms after it's soldered in place and don't be alarmed when it reads <1 ohm. There's something with the plug that makes it show up this way (wasted 2 resistors because of this).

Looking at the weight sensor pad it looks like a glorified strain gauge (as it stretches it increases resistance). The problem is the module attached to it. I would say with some certainty that if someone was to measure resistance on the traces at the pad to module connection that we'd be able to solve this whole weight sensor issue once and for all. Unfortunately I don't have the kind on money laying around to risk damaging mine. Now if someone wants to give me one to test this with then let me know (can't guarantee it'll come back in one piece though).

PM me your address I can pull mine out and send it ... sold my driver side seat but the pax side is just sitting in the garage collecting dust. Would take me a day or so to get it out of there (the pad) and mail it. Would I get it back ?

gomer_110 · 03-03-2013, 05:56 PM

Quote:

Originally Posted by sixpax

PM me your address I can pull mine out and send it ... sold my driver side seat but the pax side is just sitting in the garage collecting dust. Would take me a day or so to get it out of there (the pad) and mail it. Would I get it back ?

The plan would be to remove the white and black fabric off both sides of the pad to be able to follow the circuit traces. Would also need to scrub off the plastic covering off the traces at various spots to be able to take readings.

Assuming I'm right about the way the sensor is designed I would envision a small box containing the original control module, additional wiring, and a switch to enable/disable the airbag.

As far as getting it back: if it works then absolutely, if I can't figure it out then I'd still get it back to you the only thing would be that the fabric on both sides would be removed and the mat would have some exposed circuit traces on it.

Let me know if you're still interested.

Also just came across this: BMW & MB SRS Emulator. Obviously it's not spec'ed for our cars but for $20 it might be interesting to give it a shot and see what happens.

martin82 · 03-03-2013, 10:28 PM

I believe that the sensor pad and box relays info before and after maybe, I don't think it's just a matter of impedance.. Buy hope it is... I know someone that measure it w no success

gomer_110 · 03-03-2013, 10:47 PM

Quote:

Originally Posted by martin82

I believe that the sensor pad and box relays info before and after maybe, I don't think it's just a matter of impedance.. Buy hope it is... I know someone that measure it w no success

What I really want to do is eliminate the mat and just keep the little box with some extra wire and switch attached to it.

What would be really nice to find is one of these weight sensor emulators that exist for a lot of other cars out there that would work for us on the Z34.

Also just found this on a Mini forum and surprisingly their sensor mat module looks very similar to ours. Mini weight sensor

gomer_110 · 03-11-2013, 09:11 PM

Finally got my hands on a sensor mat. In case anyone cares this is what it looks like with the fabric removed.

Also does anyone know which wire is which going to this thing. I found that the red wire is is +12V in the service manual but that's it. That leaves me with a white (slight pinkish hue to it) and a brown. I'm guessing that the white is the common/gnd but would rather know for sure so I don't short this thing out.

josemartinrea · 08-25-2013, 09:56 AM

Hope someone will replay today... but will a 2.2 Ohm 1/2 watt resistor work too? I'm doing the install today and found out about the airbag sit. today as well. I don't have time to wait for a package :/

03-03-2013, 12:51 AM	#92 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	A couple things I noticed when I was installing my Bride Vios III: If your anal retentive like me and verify the 4.7 Ohms after it's soldered in place and don't be alarmed when it reads <1 ohm. There's something with the plug that makes it show up this way (wasted 2 resistors because of this). Looking at the weight sensor pad it looks like a glorified strain gauge (as it stretches it increases resistance). The problem is the module attached to it. I would say with some certainty that if someone was to measure resistance on the traces at the pad to module connection that we'd be able to solve this whole weight sensor issue once and for all. Unfortunately I don't have the kind on money laying around to risk damaging mine. Now if someone wants to give me one to test this with then let me know (can't guarantee it'll come back in one piece though). __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock

03-11-2013, 09:11 PM	#104 (permalink)
gomer_110 A True Z Fanatic Join Date: Aug 2011 Location: Perrysburg, OH Posts: 17,992 Drives: '11 Nismo #528 GM Rep Power: 36941	Finally got my hands on a sensor mat. In case anyone cares this is what it looks like with the fabric removed. Also does anyone know which wire is which going to this thing. I found that the red wire is is +12V in the service manual but that's it. That leaves me with a white (slight pinkish hue to it) and a brown. I'm guessing that the white is the common/gnd but would rather know for sure so I don't short this thing out. __________________ '11 370Z Nismo #528 Fast Intentions \| Stillen \| Motordyne \| Uprev \| CSF \| Zspeed \| Z1 Motorsports \| AST \| Swift \| SPC \| SPL \| Whiteline \| Hotchkis \| Bride \| Schroth \| Robispec \| Cusco \| Nismo \| Volk \| Forgestar \| Hoosier \| RJM '17 Titan Bone Stock Last edited by gomer_110; 03-11-2013 at 09:17 PM.

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03-03-2013, 08:57 AM	#96 (permalink)
WhiskeyHotel Track Member Join Date: Nov 2009 Location: Oklahoma Posts: 530 Drives: 2015 GT-R PW Premium Rep Power: 17	Yeah, it would depend on where it was measured and whether it was connected or not.

03-03-2013, 10:28 PM	#102 (permalink)
martin82 A True Z Fanatic Join Date: Nov 2011 Location: los angeles Posts: 2,636 Drives: 12 Nissan 370Z MB M6 Rep Power: 20	I believe that the sensor pad and box relays info before and after maybe, I don't think it's just a matter of impedance.. Buy hope it is... I know someone that measure it w no success

08-25-2013, 09:56 AM	#105 (permalink)
josemartinrea Base Member Join Date: Jul 2013 Location: Texas Posts: 81 Drives: 2010 Nismo Rep Power: 13	Hope someone will replay today... but will a 2.2 Ohm 1/2 watt resistor work too? I'm doing the install today and found out about the airbag sit. today as well. I don't have time to wait for a package :/