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Aftermarket seat install - please help

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6
5
Exp. Type
W2W Racing
Exp. Level
10-20 Years
SoCal
I have a ‘21 GT and I’m installing Sparco seats. I am OCD and I can’t imagine living with airbag/seatbelt lights. I’ve read a few different forums and it seems I need a stock front driver and a stock front passenger seat wiring harnesses and then I can then install the 2.2 ohm resistors for the airbag.

I can’t find the wiring harnesses I need anywhere without buying the whole seat, should I just say F it and use the wires from my stock seats? I can’t seem to find exactly where to install the resistors either.

Anyone who can help or advice or whatever would be appreciated, thank you in advance.
 

Bill Pemberton

0ld Ford Automotive Racing Terror
8,425
8,354
Exp. Type
Time Attack
Exp. Level
20+ Years
Blair, Nebraska
Good luck, as there were some changes on the 21s and it seems difficult to get some of the idiots lights over-ridden. Example --- I put the rear seat delete kit in my Mach 1 and even though this is an option, and I put in the factory delete kit, I still get a rear seat malfunction light. The good thing for that is it flashes me a warning and I just have to hit the " OK " button and it ceases to come back up. There were numerous comments from folks who did this and the only thing that worked, it seemed , was to put the seat belts back in ----OCD here also , but I don't want to take weight out to put it back.

Chatted with my mechanic , who I worked with in the Woodhouse Motorsports Division and he simply said there were some odd changes on 21s that mean it is tough to override, but often just hitting the " Ok " button will alleviate the concern.

This likely doesn't help you much, but the systems are getting harder to mask over , so just tossing this out.
 
6
5
Exp. Type
W2W Racing
Exp. Level
10-20 Years
SoCal
Good luck, as there were some changes on the 21s and it seems difficult to get some of the idiots lights over-ridden. Example --- I put the rear seat delete kit in my Mach 1 and even though this is an option, and I put in the factory delete kit, I still get a rear seat malfunction light. The good thing for that is it flashes me a warning and I just have to hit the " OK " button and it ceases to come back up. There were numerous comments from folks who did this and the only thing that worked, it seemed , was to put the seat belts back in ----OCD here also , but I don't want to take weight out to put it back.

Chatted with my mechanic , who I worked with in the Woodhouse Motorsports Division and he simply said there were some odd changes on 21s that mean it is tough to override, but often just hitting the " Ok " button will alleviate the concern.

This likely doesn't help you much, but the systems are getting harder to mask over , so just tossing this out.
Deal with extra weight or deal with a dash light. Holy Christ both options are unacceptable to a small yet very strong part of my brain… I wanted to strip all belts and buckles out completely in the back and then the front when I put in my cage/harness. 🤦🏼‍♂️
 
6
5
Exp. Type
W2W Racing
Exp. Level
10-20 Years
SoCal
maybe contact a junk yard like Parts Farm or Midway Mustang and see if they can sell one to you from a seat that unrepairable.
I actually just found Midway Mustang and it looks like they have what I need. Still pricy for what it is but less than other options…. Im going to give them a call today, thank you!
 
6
5
Exp. Type
W2W Racing
Exp. Level
10-20 Years
SoCal
maybe contact a junk yard like Parts Farm or Midway Mustang and see if they can sell one to you from a seat that's unrepairable.
Seats just showed up and of course I got mandated to come in to work today… I suppose I’ll dig into it tomorrow-
 
35
71
Exp. Type
HPDE
Exp. Level
Under 3 Years
DFW
I have a ‘21 GT and I’m installing Sparco seats. I am OCD and I can’t imagine living with airbag/seatbelt lights. I’ve read a few different forums and it seems I need a stock front driver and a stock front passenger seat wiring harnesses and then I can then install the 2.2 ohm resistors for the airbag.

I can’t find the wiring harnesses I need anywhere without buying the whole seat, should I just say F it and use the wires from my stock seats? I can’t seem to find exactly where to install the resistors either.

Anyone who can help or advice or whatever would be appreciated, thank you in advance.
Am running m my 21 Mach 1 with fixed back race seats, 6 points and rear seat delete and roll cage I’ve been through the same thing as you and can confirm I am happily running no lights on dash. It can be done! But it took A Lot of time, effort, research and trial and error to get me here. Make sure battery is disconnected and car is dead before you start. And don’t reconnect power before you have checked and double checked everything is set. (Ask me how I know!)

First thing, I wouldn’t use your stock seats for this, save them if you want to ever sell/trade the car.

I’m at the track this weekend, so can’t get you specific parts numbers, but if you want more info I can help you this week.

You can buy these from your Ford parts dept, once you see the seat diagram on screen it will be obvious.

Upper and lower seat wiring harnesses.
Seat track position sensors

(I did clean up the wiring on the harness. There’s lots of extra wiring and connectors for things like powered/heated seats. I removed what I could and taped the ends up)

Then I ordered a pair of resistor modules here:


These will be for your seat airbag connector. You could just use some plain old resistors wired in, but I thought these were way cleaner, and plugged straight into the airbag plug.

Then you will need a pair of seat belt receptacles. Again these plug into the harness, I just ordered a pair of used ones from eBay since I didn’t want to mess up my stock ones.

Finally, you will need to carefully remove the OCS bladder from your stock passenger seat. It’s perfectly doable as long as you are careful. This is the flat bladder that tells the car if someone is sitting in the seat. It has to be plugged in to keep the car happy. I tried one from another used eBay seat, but it didn’t work. I suspect it was either the wrong part number, or most likely it’s coded somehow to the car?

I removed the rear seatbelts brackets and all other hardware. Only thing you will need to leave is the rear seat belt recepticals, as they are plugged in to the wiring. I just taped mine up with bubble wrap and cable tied them down and covered with the seat delete.

The pictures below show the wiring before I cleaned it all up. I mounted the seat position sensors to the seat base in the appropriate spot, and the seat belt receivers are mounted on the planted base for 3 point use if required. The MMR resistor module is the black all taped up piece in the pictures. I used cable conduit to protect it all, taped it all up and coiled it into a neat bundle under each seat. You wouldn’t know it was there. So don’t think I’m not OCD too!!

DCAA949D-3A1D-4AA2-A363-C79E45B7A2A9.jpeg

E12C299A-0997-4DB1-AA31-E32D500A8218.jpeg

5CE65485-5B12-437A-9063-61BEE59787C6.jpeg
 
Last edited:
5
8
Exp. Type
HPDE
Exp. Level
Under 3 Years
Dripping Springs, Tx
Am running m my 21 Mach 1 with fixed back race seats, 6 points and rear seat delete and roll cage I’ve been through the same thing as you and can confirm I am happily running no lights on dash. It can be done! But it took A Lot of time, effort, research and trial and error to get me here. Make sure battery is disconnected and car is dead before you start. And don’t reconnect power before you have checked and double checked everything is set. (Ask me how I know!)

First thing, I wouldn’t use your stock seats for this, save them if you want to ever sell/trade the car.

I’m at the track this weekend, so can’t get you specific parts numbers, but if you want more info I can help you this week.

You can buy these from your Ford parts dept, once you see the seat diagram on screen it will be obvious.

Upper and lower seat wiring harnesses.
Seat track position sensors

(I did clean up the wiring on the harness. There’s lots of extra wiring and connectors for things like powered/heated seats. I removed what I could and taped the ends up)

Then I ordered a pair of resistor modules here:


These will be for your seat airbag connector. You could just use some plain old resistors wired in, but I thought these were way cleaner, and plugged straight into the airbag plug.

Then you will need a pair of seat belt receptacles. Again these plug into the harness, I just ordered a pair of used ones from eBay since I didn’t want to mess up my stock ones.

Finally, you will need to carefully remove the OCS bladder from your stock passenger seat. It’s perfectly doable as long as you are careful. This is the flat bladder that tells the car if someone is sitting in the seat. It has to be plugged in to keep the car happy. I tried one from another used eBay seat, but it didn’t work. I suspect it was either the wrong part number, or most likely it’s coded somehow to the car?

I removed the rear seatbelts brackets and all other hardware. Only thing you will need to leave is the rear seat belt recepticals, as they are plugged in to the wiring. I just taped mine up with bubble wrap and cable tied them down and covered with the seat delete.

The pictures below show the wiring before I cleaned it all up. I mounted the seat position sensors to the seat base in the appropriate spot, and the seat belt receivers are mounted on the planted base for 3 point use if required. The MMR resistor module is the black all taped up piece in the pictures. I used cable conduit to protect it all, taped it all up and coiled it into a neat bundle under each seat. You wouldn’t know it was there. So don’t think I’m not OCD too!!

View attachment 80993

View attachment 80994

View attachment 80995
I’m about to do the same thing with my 21 Mach1.

I was wondering if you had the part numbers for the seat harnesses you used?

I’ve looked around, but haven’t had any luck finding them.
 

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