Do you have a plug like this under your seats?
This is for heated seats.
If you have heated seats but not wired up, Kufatec sell a loom for heated and electric seats.
Otherwise, if you just need a 12v supply for lumbar, buy some repair wires and plug them into the fusebox, run the wire under the carpet and to your lumbar for both sides.
Bit odd they are not wired in but the rest is, have a scour for unused plugs etc and post them up if you find some.