In the E70 the Max button is no longer used for residual heat - the manual air volume button ( big one in the centre to the right of he rear window defrost) is used instead. Pages 102 and 105 of the owner's manual. When you press this with the engine turned off - o/s temp must be below 77 F and the button must be pressed within 15 minutes of swiching the engine off - rest will appear in the climate console.

BTW this is not the same as the latent heat accumulator that is/was offered in some markets. It can store hear for several days.

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07 X5 E70 4.8i
04 Z4 E85 3.0