Quick background: I have a 2011 LCI e92 (sept built) and every time I see a picture of a 2007-2010 dash I always regret not having the REST feature. I was simply jealous. California, Florida and Texas (to just name a few) fellow 3-series drivers doesn't care at all and love the introduction of the ALL feature to sync both sides temperature, but here in Canada I think REST (residual heat) is more useful.
Some months ago I came across a thread over here (
link) about buying a cable and do some coding yourself. I don't want to explain all the steps here, all the required info is over there, its just a bit long to have an in depth look... Take your time to study it if you're interested.
I've made numerous read of all the available parameters that can be changed and came across one that pretty much shocked me! Its called "REST_TASTE_VERBAUT" some quick google translate revealed that its "REST Button Installed". Interesting ? Well I thought so and made a test to change it from "nicht_aktiv" (not active) to "aktiv" (active).
After all its only a button with a LED and some marking. Its nothing like a old school hardware toggle switch.
After the feature is coded to active, first try. I shut down the car. Start the car: the ALL button that was normally always lit is off. Okay... I press it: nothing -> wow, maybe it works. I took a quick ride, then return home. Shut down the car completely, press the ALL button -> it WORKS!
I exit the car, close the door, lock the car, light is still on and its heating... Come back 15min later, light is off, I open the car its very warm !
I knew it was possible to do something, after all, the 2011 cars still have an electric water pump and all the electronic is there. BMW engineers / marketing decided to react to complaints about the lack of an ALL sync button and decided to replace the function.
Some pictures of the car completely off with the ALL button lit, its heating trust me. And the best off all: in May i'll get the ALL function back for the summer.
![](http://img845.imageshack.us/img845/5820/img0105p.jpg)