[M_Bimmer]

Yes there is...I did it....

It is not simple.

There two or so posts that describe partial installation with partial 4-zone, but none completed it, other than me, that actually achieved 100% 4-zone.

Things that need installed for ISTA+ error free installation:

1. 4-zone flap distribution assembly (located behind the dashboard)
2. 4-zone front left, center and right vents (they have controls built into them)
3. Add wiring left, center and right vents
4. Add wiring center vent to front control panel (blue connector)
5. Add wiring from front control panel to rear control panel
6. Add wiring from rear control panel to light module (front left drivers area)
7. Add wiring from rear control panel to LIN bus
8. Add wiring from rear fuse panel in trunk to rear control panel
9. Add wiring from rear fuse panel to left floor heater/temp sensor
10. Add wiring from rear fuse panel to right floor heater/temp sensor
11. Add wiring from rear fuse panel to center console fan
12. If you change out center console for B-pillar vents, then new center console
13. B-pillar right trim with vent
14. B-pillar left trim with vent
15. B-pillar to center console tubes, left and right
16. 4-zone rear carpet, or remove foam to sit over item 13 above
17. Left floor heater, temp sensor, flap assembly
18. Right floor heater, temp sensor, flap assembly
19. 4-zone rear vent assembly on center console
20. Add '4NB' FO Code via E-Sys

The dashboard removal wasn't that bad, and the distribution box needs to be changed out to really be true 4-zone, which has additional flaps required to adjust air flow to the rear cabin via the floor, and center console. Once the distribution box is installed, the other items really just get "replaced" as you put the car back together.

I bought a complete interior car harness from a VIN that had the option 4-zone option, rear heated seats, and other desired options. Then I pulled the wires and connectors required, installed those along the path of my original harness, and programmed the car.

Kid loves the ability to run the A/C full blast, and heated seats simultaneously.

This upgrades using eBay parts was under $1500, half of which was the harness. I would not use new BMW parts for this upgrade...

So 4-zone was NOT an option for the '14 535...but now I have this option.

Cheers