I can actually do without the heaters (although that leather sure does get cold in the winter). Lately, I feel that any time the temp is over 75, my back gets increadibly sweaty. I know that some of the newer cars have self cooling seats. Is there any type of aftermarket install that could be done on the 4runner?

 

There are a few posts on heaters but haven't seen any on coolers. Maybe the companies that make the heaters also do coolers. Try searching as this was pretty popular when it was colder (a few months ago).

 

I am not aware of any aftermarket seat coolers for 4runners, but seat heaters, yes, there are a few. The kits are sold on eBay quite inexpensively (quick search will reveal there are a few threads on the subject as well).

 

I'll try emailing some of the ebay sellers. Is the heating element generally installed only on the part of the seat that you sit on, or on the part your back is against as well?

 

Most of them that I have seen, the heaters are both on the seat and the seat back.

 

You can add the aftermarket heater elements ... The only brand name that leaps to mind off-hand is Rostra.

I've never heard of an aftermarket seat cooling kit...

My Recaro Orthoped has twin fans for circulating air inside the seat body (upper and lower; all fabric), and this seems to help in hot weather ...

You might consider a custom install of some small fans (if your seat has enough interior air space for circulation) ....

 

leatherseats.com sells them for the 3rd gen 4runner.
http://www.leatherseats.com/products2.asp?c=7&id=367

 

heating and cooling:

http://www.katzkin.com/05/FC/mainFS.html

hupptoy