Mercedes-Benz GLA Operator's 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.
Turn the SmartKey to position 1 or 2 in the
X
ignition lock ( page 143).
Y
To switch on: press button : repeatedly
X
until the desired heating level is set.
To switch off: press button : repeatedly
X
until all the indicator lamps go out.
i If the battery voltage is too low, the seat
heating may switch off.
Seats
101
Z