SKM

Researching retrofitting aftermarket seat heaters into my 1995 993 coupe as part of a softback sport seat installation project.

Does anyone know if the stock wiring harness & connector for a non-heated seat 993 has any unused wires in it that accommodate heated seats?

If not, any suggestions on where to get the power for the seat heaters?

Also looking for a Porsche two level/position switch in the event I decide to replace the generic two stage seat heater switch provided with the aftermarket heated seat.

Thanks!

pp000830

The socket the seat's pigtail plugs into has the wiring for the heated seats. The pins are already in your seats' plug. The plug on the seat pigtail is designed to snap apart so two added wires can be soldered to the two unused pins to go the seat heater. The plug then simply snaps back togeather, an extremely easy install on hardback seats. On the regular seats, I am told it is a bit more difficult to do heated seat as getting the seat covers off and positioning the heating grid involves a little upholstery modification under the seat skins. The fuse in the fuse box for the heated seats is already there. It is a bit large, I replaced mine with a lower amperage fuse consistent with what the seat heater kit recommends.

In my case, I mounted the heater on-off switch on the seat through the valance on the front of the seat that covers the seat motors. Makes for a very clean install. The drawback is you turn the heat on and off by feel with your fingers. Most mount the switch somewhere else such as on the center console. A more ergonomic solution with a bit more wiring involved.

The pins on the seat pigtail are labeled, pins number 1 (brown wire) & 2 (red wire)are to power the seat heater. On the wiring diagram pin one goes to a common ground point for the seat heater red goes to one of the control relays under the seat.
With this in mind, I assume pin one goes to negative on the heated seat kit and pin 2 goes to power the relay (hot). You should verify that pin 2 is hot and pin 1 goes to ground with a volt meter.

Above is a clip of the plug image from the factory wiring diagram:

SKM

Thank you! That is the exact and precise information I needed to complete my plans for this project.

Your point about retrofitting the heat grids to original seats is spot on as well. I am having the seats reupholstered so the heat grids can be installed properly as part of the job.

Since my post, I found an aftermarket seat heater kit with a rectangular two position switch resembling OEM Porsche switches. Will mount these switches in the console on either side of the e-brake.

Thanks again, very much appreciated.

nine9six

It would be nice to see photos of your install when you're finished.