5'11, 160. If you're comfortable i'll be looking into it. I remember reupholstering (if you can call it that) my little creeper for sliding under cars. soft padding bottoming out, better off laying on concrete. Seems like it encourages one into positions that you'd avoid on a hard surface but doesnt have the cushion to protect the joints once there. I havent really figured out all the science but I've stopped sitting on my wallet while driving.

In regards to the gas tank rivet thing, that reminded me of the Ford Pinto incident (documented on NPR, my girlfriend caught me with it.)

Something about 'in a crash, a bolt in the frame would perforate the gas tank.'
I can't speak to the fit's layout as I haven't needed to touch the fuel tank or remove the seat, but the Pinto story got me thinking about how many design nuances may be result of crash safety considerations.
Or yeah, cheap tricks! Studs can have pan heads and point up. A rivet may be cheaper and faster than a bolt.

 

Ok I got the car back! I need some help, at least to get the driver side sorted to the point where I know it isn't triggering the light. See the diagram above. Is this all correct? I didn't take out the civic position sensor (PS), I just left it unconnected. I am running the Fit seatbelts as the connectors are different as stated earlier.

On the passenger side I am running the Fit seatbelt and everything ugs right in. 2013 Fit, I believe 08 Si seats.

Edit: I spoke with that other guy and his airbag light came back on.

 

I'm not sure what you have the wire for the Fit position sensor connected to -- for both seats the position sensor itself is the same but the wire that connects it to the body harness is different. If you remove the wire that plugs into the position sensor from your Fit seat and put it into your Si seat it should work fine; that's what I did for mine.

I haven't swapped the passenger seat yet though so I can't comment on that yet.

 

Thanks, though I'm not sure I follow. I have the Fit position sensor plugged into the floor harness. It will not fit into the Civic position sensor, so I just left that one unconnected.


I think we are thinking the same thing, I just haven't completely removed the civic position sensor, I just unplugged it instead. So I have the Fit position sensor wire plugged in to the floor harness, with the sensor end just loose under the seat.

 

Oooooh wait I think I know what you are saying. I need to disconnect the wire from the Fit position sensor, then remove the wire from position sensor in the civic seat, and plug the Fit wire into the Civic position sensor

 

Doing some more digging. I forgot what I was doing a year ago on this. I managed to find a matching set of 2013 Fit seats and stripped them down completely. Pictured below is a set of 09-11 seats I tore down for a Recaro swap, but it didn't work out I believe because the 09-11 electronics are different than the 12-14. So yes, I found another set of seats for a 2013. In for a penny, in for a pound.


Anyway, here are some pics of today's findings.

Civic Si weight sensors. 2 wires.



2013 Fit weight sensor plug. 3 wires.



And I'm officially stumped. I think the only thing to do is take out the weight sensors from the Fit passenger seat and plug them in along with the rest of the flat, seatback sensors and plug them into the original silver box. Then attach the Fit weight sensors in somehow to the Civic seats.

I did look at the airbags as well and the pins line up between Civic and Fit so yay there!

 

I just tried a couple more things. The harness coming from the Civic weight sensors matches up with the Fit floor harness just fine.



The two upper seatback sensors have the same plugs as the Civic seats. I tried plugging them in and it made no difference...but maybe the light just needs to be reset? Maybe the weight sensors in the Civic seat will read, as the harness plug matches the Fit floor harness? It's wishful thinking. I tried my cell phone app and it doesn't even pick up the airbag light as a fault code. I have a feeling that the seatback sensors in the Civic seat are just fine, and the floor weight sensors out of the Fit seat need to be transferred over somehow.





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Thanks for staying with this, Chantastic. These posts are valuable and informative.

 

Thanks for the positive message!

Did some more digging today.





Thanks for posting the diagram above, I removed this plug.



So this what I have tried:

Removed the third plug from the silver box. Light is still on.

Replaced the first two plugs with the '13 Fit big back sensor and strip sensor, while keeping the floor weight sensor plug (third plug that's plugged in above). Light is still on.
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Replaced the first two plugs with the '13 Fit big back sensor and strip sensor, and also replaced the floor sensor with the 13 Fit floor weight sensor plug, complete with the 13 floor weight sensors. Photo below. Light is still on.



At this point since I already stripped down the 13 Fit seats I decided to go all in and I even reconnected the '13 Fit airbags. The light is STILL on. In summary, I've gone back to 100% factory in both seats, save for the position sensor in the Civic seat, which should be the same as the Fit and shouldn't be causing problems if Old Yeller only replaced the wire and had no airbag light come on.

The pins on the Civic airbags match the Fit. The pins on the big back sensor and the strip sensor also match the Fit. Is it safe to assume that these components should be interchangeable then?

The only difference is the passenger side, floor weight sensors and their harness pins. I did have to remove the nuts off of them (E18 torx) to get them off the rest of the seat frame. Maybe by taking the springs off and then remounting them, I messed them up? Or maybe they're fine, and I can run the Civic airbags, Fit seat belts, Fit position sensor wire, Civic strip sensor, Civic back sensor, with the Fit floor weight sensors + harness, and I just need to reset the airbag light? If that were to work, I'd just need to find a way to mount the position sensors. In my old Recaro swap simulated weight by pressing bolts down on top of the sensors, but it was fixed weight. Meaning that it would always be in stage one or in stage two airbag deployment, regardless of passenger weight.

Sorry for the long post! Feels like I am thinking out loud. I think I saw someone post earlier that in the event of a crash, despite the light being on, the airbags will still deploy? Is that only true if it can sense that a passenger is in the passenger seat?

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Great info Chantastic -- when you finish your seat swap and I do my passenger seat one of us should write up all this info into a how-to lol.

Sorry for not getting back to you on the question regarding the weight sensor, I admittedly don't check forums super often. I think you got it figured out but if not here's a crudely drawn example to try and make it easier.

The position sensor for the drivers side inside of the rail is identical inside between both cars. However the "inbetween connector" that connects to sensor to the harness coming out of the carpet is different. If you take the inbetween connector from your stock Fit seats and plug it into the position sensor it'll work. To my knowledge the sensor shouldn't need to be calibrated either.

All of this said I still haven't had a chance to replace my passenger seat yet; my work keeps me really busy and I'm going autocrossing for the first time in a week so I had to get off my ass and swap the CMC on my car lol. I can't comment on replacing the weight sensors but I will say that the ODS module is supposed to be reinitialized after replacement.

The only problem that HDS is Honda's proprietary diagnostic software. I have no idea if it's possible to pirate it but a trip to the dealership may be in order to have your seat reinitialized. However I'd only do that if you're sure you have everything setup correctly. Admittedly I don't fully follow what you're doing with the weight sensors because I've never really worked on weight sensors like that but if you have everything from the Fit swapped over I would imagine it SHOULD work. And if the pins match I would imagine they should be interchangeable. However if you want to make sure you could always try to find the PN for the Civic and Fit weight sensors and compare them; that's how I determined the weight sensor was the same between both seats.

All of this said you may want to call around at a few dealerships and see how much they might want to reinitialize the ODS module -- there's a chance some might do it for free because it's just an update. If not it should bill out for half a hour of labor. If you have everything swapped over and the pins match up I would imagine the module needs to be initialized and reset to get rid of the light.

I'll update this thread when I pull my passenger seat as well but it may not be for a little while still. Side note, I wonder if K-Tuner or any other Honda tuning software would be able to do things like what HDS is able to.

 

Sorry to bump an old thread, but any final updates on any of this?

Picked up a set of Si seats to put into my 2012 Fit and this has been the most detailed thread I could find! Amazing work!

In theory, if I take the OPDS unit out of my OEM seats and connect it to the strip sensors and weight sensors on the Si seats as well as swap over my seatbelts and then turn everything on -- it should work without an airbag light? Or I suppose if the OPDS needs reinitialization, the light will come on regardless.

Crossing my fingers you're still around

 

Hey everyone!

Good news: I got it working! No light! I'm a bit strapped for time so I won't be reviewing/editing the earlier posts I made, but hopefully this helps someone one out. As a refresher, I have 08 Si coupe seats (same as sedan but with the quick release) going into a 13 Fit. As far as I know, 13-14 Fits are different than the 09-12 Fits electronically. 14 Fit GE8's I believe were only available in Canada.

I went all in and sourced another passenger seat, this time from a 2013 Fit vs the former seat that I stripped which was an older model. As far as I can tell, the components are the same. I've heard about 09ish Fit's with these same Civic seats that plugged in no problem, no light. That I cannot speak to. The 08 Civic seat plugs will not match up with the plugs on the 13 Fit, the weight sensors have a different number of prongs.

Ok so, I stripped the 13 Fit passenger seat apart for the two back sensors (one square, one strip), I got the seatbelt, the entire bottom end with the rail, feet, and weight sensors. I did NOT use the 13 airbags! Here is the Fit bottom end:






Thanks to my friend in Cali who did similar work and got it working without the springs on the sensors. Once you have completed all of the above, place the two strip sensors on the civic seat. We didn't even bother gluing them down, and I only removed the strip sensor from the Civic seat because it was easy. I left the back sensor on, and then put the Fit back sensor (square one) right on top of the Civic's, then tightened the fabric overtop. I already had the silver box from my original seat installed into the Civic seat. I then plugged in all the electronics into the box, including the Civic airbags. Note: The Fit airbags mount completely differently than the Civic ones, but the connectors are conveniently the same! Remember to swap the seat belt buckles.

Once it was all plugged into the silver box, just connect the floor harness for the weight sensors. We started the car and still had the light on, but were able to connect a non Honda branded diagnostic tool up the OBD port. It was a generic one my mechanic had off off Aliexpress. It said one of the weight sensors was not reading properly. It was able to recalibrate everything, an ta-da! No airbag light. The passenger airbag off light will also still illuminate when I have a small amount of weight on the seat bottom.

Job done. Saga over. Hooray!