Thanks for the confirmation.

 

So far, I have not seen anyone with an F10 chime in on the residual heat mode. The F10 has an electric water pump.

 

I think that mainly due to this post is in E60 Discussion forum not F10 Discussion forum.

 

I tried this feature last night (1st time I use it since 2004), I could only feel the cold air coming out of the vents under the dash (footwell), not warm air !! The car had been driving for about 25 minutes and outside temperature was at 9F. No air coming out of the center vents, only vents in both footwell area.

So, this feature is broken in my car ?

 

The "residual heat" or "rest" button works via a small electric pump (auxillary water pump) that circulates water from radiator through heater core and back. The feature will produce heat until the coolant has lost all latent heat (i.e. if you keep restarting the feature after it shuts off). The pump is located on the left (aft) side of the radiator in the rats nest of water hoses.

 

I wouldn't use that feature more than once between drives because it kills your battery. I once used it twice in a row while just sitting in my car and I ended up getting all sorts of warning, the kinds of things you see when your battery is low. So if your going to be sitting in your car for more than one cycle, just start the car.