Patrick

A couple of people have expressed an interest in how I added heaters to my GT3 seats, so here is a howto (get started, anyway). Not very complete, but it should give you the idea.

Let me start off by saying that this is NOT the most economical way to go about this. However, if:
a) You have heated seats in your car already
2) You want the stock switches to work the heaters
III) You want the seats to be a "plug & play" swap
d) You don't care that it costs about twenty times as much as other methods

then this method might be for you!

My example is an 01 996 C2. Some part numbers may have to change, but I imagine that these will work for most any install.

You will need the following parts:
(one for each seat, there is no "left" & "right")
996-618-521-00 Controller
996-618-531-00 Mount for the Controller
996-653-105-01 Heating Element, Lower
996-521-539-00 Heating Element, Upper
996-612-540-01 Wiring Harness
999-650-180-40 Electrical Connector (actually just a shell)
999-650-960-40 Slide in Cover for the Shell

The total list price for all these parts is about $750.00 each seat. You should be able to work out a discount with your dealer for this much merchandise. Otherwise I'm sure you can find them cheaper. The controllers are $75.00 each, so you may want to use your existing ones.

The elements are surprisingly large. They cover pretty much the entire center portion of the seating surface. I don't recommend that you use less than the entire element provided. The upper heating element comes attached to the foam cushion. A little work with a hair dryer will separate it. Since the GT3 seat back pad has a swath of stitching across the middle, I chose to have a local upholstery shop install this pad. You could do it yourself if you can stitch. It cost me less than $100 to have that done (both sides). The upper element is about 3/8" thick, so it fills the cushion out nicely.

The lower is a different story. Since there are two cushions, and the heating element has a lot of surface area, I chose to split the element and splice the conductors.

Here is the stock lower element:


And here is where I chose to cut the element (the first split on the left, farthest from the cord):


Next, you need to fish out enough of the element to solder to. I used a razor to carefully cut the cloth backing and pull the element out the top. Be very careful as it is easy to cut the element. If you do, simply start again.


You will need to do this in four locations. The next step is to solder wires to the exposed ends of the element:


I used iron on patches (available from the local department store) to secure the wires and provide support for the soldered connection:


I used more of the iron on patch material (a thinner variety) to close up the slots in the pad. Even though the element has an adhesive backing, I think this will help keep the element from shifting once it is installed.


I don't have photos of the pad installation. The lower element is peel & stick. The element half with the factory cord goes on the rearward cushion, and the smaller section goes on the front. I wrapped cord end of the rear half under the rear of the cushion, and a good bit of the front half wraps under the front of the cushion. You will want to avoid having a large area of heating element under the seat or anywhere else heat could build up. I chose to connect to two halves together with a cheap two-pole connector from Autozone. You could also butt-splice the wires together.

The controller mounts to the anti-sub belt supprt bar, using the factory mount. This required drilling and tapping two holes in the bar:


You will also notice that I have the stock 3 point seat belt receiver wired into the same connector.

That's about all I have on the subject. They look and work great!

Patrick