This is the heated/electric seats taken from an Alfa 164. The heated seats switch is a common part with the Alfa 164 & Alfa 33.

These are the part numbers for the heated/electric seats for the Alfa 164. The reason why this control panel was used as parts is just the switch frame which is phased out from Alfa.
The switch itself is still available from Alfa while these lines are written in 2014.

This is the Alfa 33 907 Series handbrake lever decorative box. The heated seats switches are placed on the slanted surface.
I have measured the distance so that the switch frame is correctly placed. Since there is no second chance to correct the position of the switch frames, taking accurate measurements is very important.

After careful cutting and filing, the switch frames are installed.

The handbrake box is restored back in place. 

This is the heated pad intended for the seat base. This is a new old stock item which was sitting for ages at a local Alfa shop.
 

This is the heated pad intended for the seat back.
The heated pad for the seat back is phased out from Alfa and the only compatible solution is the pad from SAAB 900. This pad has the correct resistance of 0.8 Ohm and the correct shape for the Alfa 33 seat.
The original manufacturer is SCANDMEC, Sweden which is the original supplier for nearly all auto makes. The resistance for the seat base pad is 1.2 Ohms whereas the seat back pad is rated at 0.8 Ohms. The logic behind is that the seat base should emit more heat than the seat back as the passengers during winter have the thigh protected with just a pair of trousers as opposed to the back which is protected with the coat.

Since this project involves the help of the upholstery shop, I decided to have them do the installation of the heated pads.
This is the seat base which has been during the past repaired. You can see the new foam on the sides of the base. 
The heated pad will be placed on the middle of the base.

Constantine has been very helpful explaining all the steps. He is making a mock-up test to see where the pad should be placed.
The pad has adhesive on the bottom part so that it sticks to the seat foam.

This is the adhesive side of the pad. Note the circular button on the middle.
It is the pad thermostat which cycles the pad on/off when the temperature reaches a specific value.

Apply the adhesive starting from the middle.

Then the pad is evenly pressed so that it adheres to the foam.

Place the seat cover and secure the cover wire to the retaining spring.

The cover wires are attached to the retaining springs and the cover should be wrapped around the seat base.

Constantine now pulls the nylon cord to stretch the cover on the seat base.

The nylon cord is now in place and the hog rings firmly attach the seat cover to frame.

This is the seat back heated pad. Constantine trims the pad just a little bit on the sides of the pad.

The openings on the pad must be enlarged a little bit so that the retaining springs pass through.

Note the enlarged openings where the seat cover retaining springs pass through.

A little more trimming.

Trial fitting.

The pad is aligned and the openings properly trimmed.

The seat cover wire perfectly lines up with the retaining springs position.

The heated pad is now ready for installation. The rear side is adhesive as the base heated pad.