Rear Window Heater Issue

[Mattdaniels94]

Hi All, I bought my Z4 three years ago and as far as I can remember, the rear window heater has never worked. With the spring setting in, I’m fixing some unresolved issues on the car to give it some love. One of those is of course the rear window heater. Starting at the top, I’ve checked the fuses and they are fine as well as checking the window itself. Unplugging the connectors and checking the current, that’s passing nicely through the window so no issue there. When the switch is on and illuminated, I’m not getting 12V on the left plug. It doesn’t change at all when the switch is pressed. I’ve read about transportation mode but the air con and blowers etc are working fine. My gut feeling is a relay or a fault in the wiring loom. I’ve read about a K13 relay but cannot seam to locate that. Would anyone know where I might go next with this? Thanks for your help.

[Sidewaze Samm]

I’ve read about a K13 relay but cannot seam to locate that.

From memory (it was about 5 years ago...) you need to drop the actual fuseboard down from behind the glovebox, flip it over (being careful not to short out on the chassis) and there you will find more fuses and relays.