Aftermarket seat replacement. Quick how to. With electrical info.
7/2/18, 06:07 PM
#1
Aftermarket seat replacement. Quick how to. With electrical info.
Posting this up as a public service announcement. I hope this is helpful to someone. No pics, but very detailed words. This mainly covers the electronics involved.
This is all very straightforward. If anything here doesn’t make sense, this isn’t a project for you. :-)
Drivers Seat
There are only two systems here to worry about. The seat position sensor and the airbag connection.
The airbag posiiton sensor is the easiest. You are going to disconnect and install the proper resistor in the circuit. The car looks for the proper resistance in the circuit. If this system is just disconnected by leaving unplugged or simply connected, you will get an airbag light.
With the factory seat out of the car, I measured the resistance of the airbag at 2ohms. Mine is a 2012. YMMV. Or your ohms may vary. I soldered a 2ohm resistor in-line and was done.
Next is the seat position sensor. S197s use a dual stage airbag depending on seat position. The sensor is a Hall effect unit that references the seat track. You have a couple options here, you can do the measuring and math and figure out how and where to mount. What I did was note whether the unit was engaged or not in my normal driving poison and set it there permanently. In my case, short legs long torso, the sensor was not picking up metal. So I wrapped it in electrical tape and zip tied it away under the seat. In any event, the Hall effect sensor needs to be connected or you will throw a code.
Passenger Seat
Has all of the above, plus the joy of an occupancy sensor. This is an air bladder that senses an occupant and their weight.
My my workaround was simple and easy, but does not maintain full functionality. It is possible to do so, but was way more hassle than the benefit and I didn’t want to tear my seat apart.
I fooled the sensor into thinking the seat was occupied full time by sandwiching the bladder under the seat mount. Another owner did the same thing by zip tieing it into a burrito. Same effect. What you are doing is putting pressure on the bladder. If the bladder is just laid on the floor, you will not get an error message, but the passenger airbag will not deploy either.
The car now thinks there is a person there all the time and will need the seatbelt taken car of. This is easy too, You can either hard wire the seatbelt wires to fool it. Or you can just disable the chimes and light by doing the standard seatbelt bypass dance, which is what I did. Key on, buckle unbuckle, etc...
Hope this helps somebody.
The seats I installed were the Corbeau A4s. Suede with 1” shave and anti.sub cut. Seats and brackets are very high quality. The tracks a bit less so. I ended up replacing he smallish hardware and adding some larger washers, but generally pleased.
This is all very straightforward. If anything here doesn’t make sense, this isn’t a project for you. :-)
Drivers Seat
There are only two systems here to worry about. The seat position sensor and the airbag connection.
The airbag posiiton sensor is the easiest. You are going to disconnect and install the proper resistor in the circuit. The car looks for the proper resistance in the circuit. If this system is just disconnected by leaving unplugged or simply connected, you will get an airbag light.
With the factory seat out of the car, I measured the resistance of the airbag at 2ohms. Mine is a 2012. YMMV. Or your ohms may vary. I soldered a 2ohm resistor in-line and was done.
Next is the seat position sensor. S197s use a dual stage airbag depending on seat position. The sensor is a Hall effect unit that references the seat track. You have a couple options here, you can do the measuring and math and figure out how and where to mount. What I did was note whether the unit was engaged or not in my normal driving poison and set it there permanently. In my case, short legs long torso, the sensor was not picking up metal. So I wrapped it in electrical tape and zip tied it away under the seat. In any event, the Hall effect sensor needs to be connected or you will throw a code.
Passenger Seat
Has all of the above, plus the joy of an occupancy sensor. This is an air bladder that senses an occupant and their weight.
My my workaround was simple and easy, but does not maintain full functionality. It is possible to do so, but was way more hassle than the benefit and I didn’t want to tear my seat apart.
I fooled the sensor into thinking the seat was occupied full time by sandwiching the bladder under the seat mount. Another owner did the same thing by zip tieing it into a burrito. Same effect. What you are doing is putting pressure on the bladder. If the bladder is just laid on the floor, you will not get an error message, but the passenger airbag will not deploy either.
The car now thinks there is a person there all the time and will need the seatbelt taken car of. This is easy too, You can either hard wire the seatbelt wires to fool it. Or you can just disable the chimes and light by doing the standard seatbelt bypass dance, which is what I did. Key on, buckle unbuckle, etc...
Hope this helps somebody.
The seats I installed were the Corbeau A4s. Suede with 1” shave and anti.sub cut. Seats and brackets are very high quality. The tracks a bit less so. I ended up replacing he smallish hardware and adding some larger washers, but generally pleased.
Last edited by 759Rider; 7/2/18 at 06:11 PM.
7/2/18, 06:53 PM
#2
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hmmmmmm . . . . thanks very much for the PSA . . . seems like that might all result in some undesireable airbag behavior if they are ever needed? not sure what the computer is doing with all that info, some of which is now incorrect
I have been thinking about track seats also (or track seat, singular) but I'm thinking maybe the best plan would be to forget about all the airbag stuff when the track seat is installed, let it throw the codes or whatever; but have a quick-change setup so the factory seat can be easily reinstalled for daily driving.
does that make any sense?
I have been thinking about track seats also (or track seat, singular) but I'm thinking maybe the best plan would be to forget about all the airbag stuff when the track seat is installed, let it throw the codes or whatever; but have a quick-change setup so the factory seat can be easily reinstalled for daily driving.
does that make any sense?
7/2/18, 07:13 PM
#3
Hi Bert.
Thank you for the thoughtful reply.
We we are all grown men here and have our own tolerance for risk and return I would never tell another man how to mod his car. I can only share my experience and hope that it is helpful to others.
I am personally comfortable enough with my own understanding and experience with electronics to be confident that I have safe and functional front airbags. But all others should proceed with their own level of comfort.
Switching seats is fast and a great idea. My factory seats were trashed, cloth, and disgusting. So they had to go anyway.
edit to add: airbag codes can be tricky. I don’t pretend to know all the nuances. I do know that some SRS codes are stored in a separate area that is not clearable by common code readers. So if you go through the track seat swap, be aware of this.
Let us all know how you proceed.
:-)
Thank you for the thoughtful reply.
We we are all grown men here and have our own tolerance for risk and return I would never tell another man how to mod his car. I can only share my experience and hope that it is helpful to others.
I am personally comfortable enough with my own understanding and experience with electronics to be confident that I have safe and functional front airbags. But all others should proceed with their own level of comfort.
Switching seats is fast and a great idea. My factory seats were trashed, cloth, and disgusting. So they had to go anyway.
edit to add: airbag codes can be tricky. I don’t pretend to know all the nuances. I do know that some SRS codes are stored in a separate area that is not clearable by common code readers. So if you go through the track seat swap, be aware of this.
Let us all know how you proceed.
:-)
Last edited by 759Rider; 7/2/18 at 07:32 PM.
7/2/18, 07:41 PM
#4
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Good mod and thanks for sharing. Adding termination resistance to trick the airbag system into "everything is ok" mode is what I would do also. This way it will fire all available airbags if and when the time comes.
A lot of people think the worst thing the airbags can do is not go off. But believe it or not the worst thing the airbags can do is go off unintentionally. All those checks the system does is to verify operational integrity of the electronics to prevent unintended firing. If something seems off the whole system is switched off and the airbag light comes on to notify driver.
Post some pics of the seats when you get a chance, curious to see them in the car.
A lot of people think the worst thing the airbags can do is not go off. But believe it or not the worst thing the airbags can do is go off unintentionally. All those checks the system does is to verify operational integrity of the electronics to prevent unintended firing. If something seems off the whole system is switched off and the airbag light comes on to notify driver.
Post some pics of the seats when you get a chance, curious to see them in the car.
7/2/18, 09:34 PM
#5
Monster.
Thanks for the note. I keep looking at your build and liking it more and more. I like the factory Recaros a bunch. And looked hard for them, but nothing came to the top. I also really wanted seats that could use traditional anti.sub straps, hence the Corbeaus. I am now going back and forth between a harness bar or a four point cage. Leaning towards the cage. Mostly a track toy anyway. :-)
Anyway, the car is in my storage unit right now, but I can emsil or post you some pics when I pull it out for the July 4th drags. I got the suede and they feel great.
The A4 seats are tight. I am a slim dude with a 32”waist. And there isn’t much wiggle room. They also make a “wide” version, that I would recommend if you have any doubt if you are wide or not.
Thanks for the note. I keep looking at your build and liking it more and more. I like the factory Recaros a bunch. And looked hard for them, but nothing came to the top. I also really wanted seats that could use traditional anti.sub straps, hence the Corbeaus. I am now going back and forth between a harness bar or a four point cage. Leaning towards the cage. Mostly a track toy anyway. :-)
Anyway, the car is in my storage unit right now, but I can emsil or post you some pics when I pull it out for the July 4th drags. I got the suede and they feel great.
The A4 seats are tight. I am a slim dude with a 32”waist. And there isn’t much wiggle room. They also make a “wide” version, that I would recommend if you have any doubt if you are wide or not.
Last edited by 759Rider; 7/2/18 at 09:36 PM.
