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

martin82

U will need the weight sensor pad and wiring... there's no way around it for now.... seems like there is some sort of communication between the weight sensor and air bag module and a simple resistor will not work. For now I am living with flashing air bag lights, my seat is a 1 piece bucket so not sure where to send the wire for the weight sensor... I could do it from the 6th point harness but the wires could get cut up when moved back and forth....

dansracing

I am installing my seats now and after removing the passenger seat there are 3 connectors. One for the weight sensor, and at least one for the airbag. Not sure what the third one is for yet. Will keep posting as I complete the job and figure it out.

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martin82

air bag has 2 wires.... and 1 weight sensor...

dansracing

The third connector is the seat belt sensor. Taking the seat apart now to get the weight sensor out.

There are Three plugs on the passenger side seat in a 2012 Nismo.

Yellow Plug = Airbag (use the resistor)
Skinny White Plug = Seat Belt (runs to the seat belt, pretty simple to find and replace)
Medium White Plug = Weight Sensor (remove and replace in the new seat and plug in)

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martin82

You do not need to plug in the sensor belt... I run without them clipped on so no more "no belts light"

surprised you don't have 4 connectors, my 2012 base+sports had all the heated wire/power seat stuff there... (I retrofitted them before I got recaro's)

dansracing

Thanks Martin....

Completed the passenger side, got lights at first but did the reset function (page 1 link) and it worked great. No more lights.

NOTE: I had planned to leave the car off, do the seat, plug everything back in before I ever re started the ignition and was going to hope for no lights. In the mean time, the wife goes out and turns the car on to re set the clock for me with everything un plugged I'm assuming that it put the system in trouble mode so at first plug in I had lights.

Again, after the re set process all is well! Will post pictures when completely finished.

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dansracing

For the 4.7 ohm resistor. They have a +/- value to them and can vary within 5% I think. When I went to a local electronic store, they had several different looking 4.7 ohm 1/4 watt resistors. After measuring several of them, only one brand of the many that were there measured consistently 4.7 on the money. I purchased those and I have had good luck with the lights on my install.

However:
I'm not convinced on the weight sensor and how it actually works. When you remove it from the OEM seat, it sits on top of about 2.5 inches of foam, plus the there is a spring mesh under the seat which allows your but to sink down into the seat.
On my racing buckets, putting the sensor under the cushion and on top of the hard plastic or CF seat surface, the sensor sits static with no movement when you sit on it. The sensor can un arm and no lights will come on and you will NOT have a passenger side air bag.
The same sensor, alerts the car that the seat belt is not fastened if a person is sitting there. So theoretically, and if you have all of the harnesses plugged in (weight sensor, seat belt sensor cable, and SRS resistor in place) and you can sit in the passenger seat without the seat belt on and the light and alarm does not sound. It tells me that the weight sensor is not functioning correctly and it does not think someone is in the front seat.
I'm almost thinking that there should be some sort of pad under the sensor so it can have movement when someone sits on it. I don't think it works like a flat surface scale.

Just thinking......

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martin82

I actually didn't know about the weight sensor and seat belt being together, I'll give that a check!!

dansracing

I was speculating because the drivers side is hard wired into the car. If it starts, it looks for that seatbelt to be fastened no matter what.
For the passenger side, it only calls for the seat belt if someone is sitting there. I have to assume that the weight sensor is part of that car logic.

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martin82

I would like to bypass the passenger weight pad and leave the air bag on at all times....... but didn't get a chance to look at it...

dansracing

I want to do that too but have no idea how. Get to work on it man! =)

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martin82

haha its not a simple resistor!!!

dansracing

Ok, here is another teaser.

I have my seats installed and have no lights on regarding SRS or seatbelts etc. I decided to test the system by having my wife sit in the passenger seat and not fasten the seatbelt to see if its related.
She got in, I started it up and the "airbag off" light illuminated and the "fasten seatbelt" chime did not activate although the small seat belt light was on, on the instrument cluster.
I turned the car off, she got out, I re started it and no lights what so ever.

So it tells me that something is going on with the weight sensor. I'm thinking its in a position on the seat where not enough weight is being seen and it thinks a small child or light weight is in the seat so its dis arming the passenger bag.

Since i have never had a small child in the front seat, does anyone out there know if the air bag off light illuminates when a child is in the front seat?

Next I am going to try to re position the weight sensor since there is no movement on the racing seat bottom, I'm thinking that the sensor is not positioned in a way that when an adult sits in it that it sees all the weight.

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dansracing

I believe I have the setup. Make sure if your doing this DIY that you check the resistors that you buy and make sure they are dead on 4.7 ohm's. Thats number one.

Number, two..... Once you remove a seat and dis connect the under seat plugs. Don't turn the car on until you are finished mounting the resistor on the yellow plug and re plugging the seat belt, and weight sensor cables. Otherwise you will have to do the "SRS reset" procedure from the link on page one.

Last. What I have found is that the position of the weight sensor pad is critical in order to make sure the passenger side air bag is armed when you have a passenger. In the case for my seats, I tried several positions to make it fail to arm and arm. The best position in my seats was to set the sensor pad farther back in the seat than you would imagine. The front edge of the sensor pad is setting about 4 inches back from the front edge of the seat. The small ECM box that is mounted to the back of the pad has to be pushed up the seat back a little. Depending on how thick your back cushion is, you will not notice the box against your back when you sit in. Basically, you may have to move the sensor around a bit to find the best spot in your seats for ensuring that it arms.

Good luck everyone!

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Mr&Mrs

I will be doing this soon. Why can we not just unhook the battery like I did with my steering wheel AirBag removal/install? If you leave it unhooked until complete when you power back up the car it never knew anything was done.

Nice write up btw thanks!

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