DIY: Installing Heated Seats in a 2nd Gen from Junkyard Parts

[Regardie]

Hi All,

So I have finished the install of heated seats in my 97 L just as the weather got cold. Here is how it's done in words, no pictures because I'm lame and forgot to take any.

There is no wiring in a 97 L sedan for the heated seats and switches, so this involves some electrical work.

Part 1:

First acquire some heated seats, switches, a relay, and an under seat wiring harness.

I went to a u-pull-it and found an Outback with the winter package and cloth seats that I was able to remove. (A note about removing seats: most likely 3 bolts will come right out. The 2 in front and the outside one in back. The two in back on the hump are more trouble. The top one might come out with some PB Blaster and a breaker bar to get it moving but the bottom one almost definitely won't. On my car I ended up breaking the welds on the nut behind that bolt trying to take my seats out. You will find that nut exposed under a heat shield under the car. Where the bolts are all 14mm, that nut is 17 mm and you can get a wrench on it and hit it with some PB Blaster as well and given some time work that bolt out.) I disassembled the seats in the yard to get the heater elements. Take a big pair of electricians needle nose pliers with you as you will need to remove the seat covers which are held on by hog rings. A hog ring is a bent metal wire used to close sausage, build fences, and hold upholstery on to seats. You will find that there are a bottom and top heater element. Make a note of which element came from where as I didn't and had to move a back element when things did not line up.

If you like the seats, you could just buy the seats and save yourself some trouble, but I had installed a leather interior from a GT in the spring and wanted to heat them.

The heater elements look like a big piece of felt with a wire coming out of it, kinda like an electric blanket, so if you go for the quick and dirty removal method and use a knife to cut them out, the felt thing is the important part, not some padding like I thought as I started to disassemble the seats.

https://sl-i.net/FORUM/images/imported/2012/01/IMG_6333JPG-1.jpg

The passenger side, larger is for the seat bottom, smaller the seat back. You can't see it on the bottom piece but there is some exposed wire that should be on the bottom side.

I checked the resistance of the elements with a meter when I got them home to make sure they were good (probably should do that in the yard before taking them out of the seats, might save you some work later) and tossed them in the washing machine to clean them up some. I then hung them up to dry.

Oh, the guy in the yard thought I was nuts when I came out with these 4 pieces of felt, had never seen that done before, and he looked like he had been there for quite awhile.

Now that the seats are out of the car, you can get get to the wiring harness under the rug. The harness runs to the passenger footwell so pop off the passenger side door sill, and the plastic piece under there to expose the wiring harness.

Make a judgement call on the quality of the carpet. I judged crap and went at it with a utility knife and cut it open to get the harness out. You need to pull the center console as well. Take the panel with switches with you. There are 2 connectors under the drivers seat, 1 heater and 1 seatbelt. There are 3 connectors near the gear shift that you need to separate. There is one connector at the parking brake, 2 connectors for the seat heater switches, and one connector for the passenger seat heater. Under the passenger seat is also a ground point, unscrew that as well. Under the kick panel are 3 large connectors, separate them. The Outback harness continues down the side of the car to the back somewhere, cut that part off or spend days trying to remove it.

Above the connectors in the kick panel will be a relay with a pink connector. Take that relay, connector, and as much wire as you can since you won't have that in your car, unless you have rear accessory power in a wagon.

Next up, how to strip and prep a wiring harness. :smile:

[Regardie]

Part 2:

Prep the wiring harness.

So from all that wire you took out, you only need a little bit of it to make the seats heat up. Unwrap the electrical tape from the harness. You need the wires that go to each switch, one blue and one white, and the seats themselves. From the 3 near the gear shift, you only need the natural one that provides the light for the gear selector in an automatic, it should have a white with yellow stripe wire and a yellow with blue stripe wire. It's R5 in the wiring diagram for the Lighting (Tail Light - Illumination Light etc.) System. You also need all the black wires and the ring that goes to the ground point.

From the 3 connectors at the foot well end of the harness (R1, R2, and R3), you need to remove 1 wire from each connector. From R1 you need to pull the Blue wire in pin 2, that is the power wire for the heaters. From R2 you need to pull the White / Yellow wire from either pin 2 if R2 is 20 pin or pin 6 if R2 is 24 pin, that's one side of the switch light. From R3 you need to pull the Yellow / Blue wire from pin 18, that is the other side of the light circuit. On the connector, you will see a bit of plastic that looks like it might hold the pins in, well it actually does that. Pry it up on the side that has the pin to remove. Use a jewelers screwdriver to release the pin and pull it of of the connector.

So now use some electrical tape and make a new harness from the bits you have saved, the switches, seats, and ground wires. Solder all the grounds together to the ground wire with the ring.

Congratulations, you have just made a heated seat harness that will work along side your current harness.

https://sl-i.net/FORUM/images/imported/2012/01/IMG_6329JPG-1.jpg https://sl-i.net/FORUM/images/imported/2012/01/IMG_6330JPG-1.jpg
https://sl-i.net/FORUM/images/imported/2012/01/IMG_6331JPG-1.jpg

It looks something like this.

Next up, seat upholstery 101. :shock:

[Regardie]

Part 3: Seat Upholstery

By now we have discussed what you have to do to get your seats out of the car. You have to take your seats out to do this. Oh, if you can't get the bolts loose, you could take the seat bottom off of the rails. There are 4 bolts in the corners, you might have to move the seat back and forth to uncover them.

With the seats out and in a comfortably warm location, start to disassemble. Take off the side pieces. The cover for the seat height adjuster (if fitted) pops off from the top. There are 2 bolts and a #3 phillips screw to take the seat back off. My seat back had a zipper along the bottom. I had to unzip the seat back and slide the seat cover off about halfway, like taking a pillow case off. Then you can get to the point that you can attach the heating element with hog rings.

Now would be a good time to talk about hog rings. You will find your hog rings all rusted when you take apart your seat. You can bend them back into shape and reuse them for the most part. Or you could do what I did. Call around to the local interior repair shops and see if you can buy a couple dozen hog rings from them. I found a shop a few towns over that rebuilds classic car interiors and they ended up giving me an envelope full. :grin:

Then you need a tool to put them in. It's called a hog ring plier. The difference from regular pliers is a small groove to hold the hog ring in place. Harbor Freight has a couple for under $10, one that is listed as in store only, but my local store had none. I found a set for $10 at the Home Depot, outside in the chain link fencing area. They were not too good, more for fencing so I eventually found the HF version, much better.

https://sl-i.net/FORUM/images/imported/2012/01/IMG_6334JPG-1.jpg

There they are with the envelope of hog rings.

Under the foam in the seat back I found a metal bar that the hog rings can clamp onto to hold the top of heating element in place while i pulled the seat cover back down.

The seat bottom has a bunch of hog rings holding it on around the edge, each clipped through the material around an inserted wire. At the back of the seat is a plastic clip that has to be pulled from the frame. Just grab the cover and pull it toward the center until the clip is free at one end and then work it free to the other end.

There are a few hog rings under the seat cover that have to be pulled to get the heating element into place and then they need to be replaced or your seat cover will look wrong.

Install the heating elements and put the seats back together. I found that the wires coming off the heating pads should be to the outside of the car. Try not to mix them up as I did and have to take a seat back apart.

Next up: putting the wire into the car.

[Regardie]

Part 4: Getting the wiring in place.

By now you should have the seats out of your car. You really do need to get them out of the way. I found that I needed to pull the gear shift knob to get the center console out. The center console has three screws in the storage box, two screws holding the switch cover in place, and four(?) more screws that hold the center console to the floor.

Now would be a good time to vacuum up your interior while everything is out of the way.

Remove the passenger door sill with a flat screwdriver or an interior removal tool. Under the door sill the carpet is clipped into another piece of plastic. Unclip the carpet and pull that piece of plastic. Near the front of the door there are two plastic nuts that unscrew and near the back of the door you need to work it out from under the center pillar trim.

https://sl-i.net/FORUM/images/imported/2012/02/0003JPG-1.jpg

The carpet is held down under each seat with two interior clips, pop them with your interior tool.

Now you can work your new harness under the carpet over the hump and under the driver and passenger seats. Unplug the connector for the gear selector light, you won't be using it, and replace it with the one from your new harness. All your black ground wires should be soldered to the wire with the ring, remove the screw on the ground point under the passenger seat and add the new ring to the one already there and tighten it back up.

You should now have three wires left to run down to the passenger footwell, a Blue, White / Yellow, and Yellow / Blue. Just like you pulled the pins from R2 and R3 from your donor harness, you need to pull the same pins from your installed harness and replace them with your seat heater harness pins.

Wires tagged into existing harness, ground wires to the left, Blue, White / Yellow, Yellow / Blue headed to the right.
https://sl-i.net/FORUM/images/imported/2012/02/0011JPG-1.jpg

If you have a rear accessory power outlet, there is a Blue wire already in pin 2 of R1, use a splice tap from the Shack to splice into the existing wire. You would also then have the rear power supply relay with the pink connector and you are done.

Most likely, there will be nothing in pin 2 of R1 where the Blue wire goes and you have some work to do. I was in that boat so this is what I had to do. Acquire some blue and yellow splice taps (the kind that let you add a wire to an existing wire) and some 12 or 14 gauge stranded wire and an inline fuse holder and a 20 amp fuse.

On the pink connector on your relay there will be four wires, Yellow / Red, Green / Red, Black, and Blue. You need two wires to run across the front of the car to the fuse box area, for the Yellow / Red and Green / Red. The Green / Red gets spliced into a matching Green / Red under the drivers side dash at connector B37/I2 pin 17. The Yellow / Red gets the inline fuse and then gets a yellow splice into a Blue wire above the fuse box in a grey three pin connector F41. Either Blue wire there will do. The Black wire gets to splice into the Black wire at Pin 5 of R1/B97 in the passenger footwell. I put a female spade connector on the blue wire and stuck my remaining floor harness wire into it and taped it up.

From Left to Right: Relay, R2, R1, R3
https://sl-i.net/FORUM/images/imported/2012/02/0013JPG-1.jpg

Blue wire at fusebox with a Yellow tap for power
https://sl-i.net/FORUM/images/imported/2012/02/0001JPG-1.jpg

In Line fuse holder. Mine needs to be cable tied still.
https://sl-i.net/FORUM/images/imported/2012/02/0002JPG-1.jpg

Your relay should then be able to clip right back into the hole up in the passenger footwell.

https://sl-i.net/FORUM/images/imported/2012/02/0014JPG-1.jpg

Next up: Testing before reassembly.

[Regardie]

Part 5: Testing

Before you get all excited and put everything back together a little testing is in order. Start the car and turn on the lights. Your new switches should light up. If the gear selector lights up but the switches don't, the wires are in right, you just have burned out bulbs in your switches. I should have a post about how to fix your switches in the electrical section soon.

Now turn the driver's switch to low. The amber light should light up. That's good. It means that you have power to the system. Now check for voltage with your multimeter on the connector for the seat between pin 1 (ground - Black wire) and pin 4 (hot - Black / Red). Should be 12 or so volts. Switch to the high position and check for voltage between pin 1 and pin 3 (hot - Red / White) and pin 3 hot and pin 4 (now ground). Repeat for the passenger side. Pin 1 Black, Pin 3 Red, Pin 4 Blue / Green.

Troubleshooting

If that did not work the way you thought it should, start tracing from the beginning of the system. Pull the pink connector from the relay. Check for voltage between between pin 3 Black (ground) and pin 2 Yellow / Red (power to the system). If nothing, you did remember to install the 20 amp fuse in the fuseholder right? If so, you probably have a bad crimp on the Blue wire at the fusebox. Check for voltage between pin 3 and pin 2 Green / Red. If nothing, bad crimp at B37/I2 pin 17. This is the power to energize the relay. Check fuse number 3 in the fuse box as well.

If you have voltage there, reinstall the relay and check for voltage between pin 3 and pin 4 Blue. If nothing, you have a bad relay, replace the relay.

The next point of failure would be all those ground wires that you connected together. I soldered them together in the car in the cold (you built yours in the house before you installed it, right?) and missed one under the carpet that went to the driver's seat connector. Took me a while to find that problem. There was some disassembly of the passenger side stuff that was foolishly installed before testing. I make the mistakes so you don't have to.

There is always the possibility that your switches are bad. One set I got, the drivers switch was kinda toasty.

Next up - put everything back together.

[Regardie]

Part 6: Put it all back together

By now the interior of your car is a wreck and parts are everywhere. So you might as well take apart the center console and pull the heater control and replace the bulbs. Pull the rear defrost and cruise control switches and fix them as well. All done? Good.

Use some electrical tape to attach your new harness to the existing harness under the door sill and under the passenger seat. Reinstall the carpet clips, the plastic piece that protects the harness and the fuel lines (you did notice the fuel lines under the passenger door sill?). Clip the carpet back down and put the door sill back in place. Install the center console with your new switch plate. Put your seats back in, remembering to attach the new connectors for the heater elements. I used some Permatex thread protectant on the seat bolts to keep them from seizing again. I am hoping they don't vibrate loose too soon.

Start it up and enjoy the heated seats! :grin:

[Wiscon_Mark]

Hey, this is a great writeup! I'd love to move it to the DIY section.

You didn't happen to take any pictures did you? If you didn't, I still think it's DIY worthy, but pics are always useful :grin:

[Regardie]

Sad to say I was rushing to get the work done and did not remember to take pictures. Please move it to the DIY section and I will try to get some pictures together.

[Regardie]

Bumping this to the top as I am adding some more pictures and it will make it easier for me to find,