Mercedes-Benz GLA-Class 2015 Owners Manual - Manual (Page 103)

Therefore, do not switch the seat heating on
repeatedly.
The three red indicator lamps in the button
indicate the heating level you have selected.
The system automatically switches down
from level 3 to level 2 after approximately
eight minutes.
The system automatically switches down
from level 2 to level 1 after approximately ten
minutes.
The system automatically switches off
approximately 20 minutes after it is set to
level 1.
X
Turn the SmartKey to position 1 or 2 in the
ignition lock (
Y
page 143).
X To switch on: press button : repeatedly
until the desired heating level is set.
X
To switch off: press button : repeatedly
until all the indicator lamps go out.
i If the battery voltage is too low, the seat
heating may switch off.
Seats
101
Seats,
steering
wheel
and
mirrors
Z