Every day a school day on a forum
dunno if I would or not TBH, but if redoing the covers anyway I suppose siting the control would be the hardest part.
Its actually pretty straightforward.
If buying a kit such as a Waeco ones, the cabling and switches are included and you just run the cabling to the seats in the most appropriate way for your installation (so routing will depend on switch location and
battery location for example) and plug the bits in.
So to give an example of the one I did back in 2008 on my 2005 RAV4, I was swapping out the cloth seat covers for Leather covers, so took the seats out and ran the cables to go underneath the seats.
Ran from the front dash area along the centre console and then to each seat position under the carppet, using existing cable runs wherever possible
Waeco supplied colour-coded cables - I used Blue for the Drivers side and Black for the Passenger.
Then have the cable pop up in the most suitable place. I came up where there was existing cabling seat (the Yellow cables will be for the side seat airbags and the other cable in the corrograted conduit would be the seat pressure sensor).
The Weaco cable has just three wires - one will be ground, the other two will be for used for High and Low. As you can see, the wires are not particularly heavy - seat heaters are pretty low intensity and don't have to draw a big current to be effective.
Then fit the heater controls.
The switches fitted will depend on the Heater system. Some OEM heated seats have multiple settings (I think VWs have about 5!); some, like the Corsa I have now, just have an On/Off (I do wish it had a high/low as it does get pretty warm!); Most I think are maybe the high/low option, which is what the Waeco ones I fitted were (they even had an "L" and "R" on the switch which was a nice touch).
I did actually make a little tweak to the kit and added an LED indicator into the circuit for each switch that would go Orange in the "I" (low) setting and Red in the "II" (high) setting, but that was the only change I made and it was not necessary, just something I wanted to do.
Switches were in a very typical place for this kind of accessory and just used existing dash blanks, making holes as needed.
And the final setup, with the newly covered seats back in place.
(as an aside, the photo above also shows the aftermarket Cruise Control stalk from the 'Gold Cruise' kit from Conrad-Anderson on the lower left of the Steering Wheel binnacle. The little white bits on the end are the three speed presets you can engage to take the car automatically to your preferred speeds rather than driving to a speed and then engaging cruise. That really is much better than OEM Cruise
)
Posted all the above really to say:
a) Yes, this is an absolutely and very doable thing.
b) No, it is not a complicated process and really is a DIY process if someone wanted to do it themselves. If someone is happy working on their own Campervan/Motorhome, this is well within their possibilities I would say.
The most complex part is actually properly fitting fitted seat covers. My seat covers were full replacements, with the originals removed and the replacements installed, which does need some specific tools and whilst I was able to do the rear seats myself, I actually got a company to fit the new front covers - but I handed the two seats to them, old covers removed and seat heater pads in place ready for them to fit the cover, so the fact I now had heater seat pads was irrelevant to their work.