Date of printing:

01/23/2022

Online Owner's Manual [In depth | Climate control | Operating the auxiliary heating system]

Owner's Manual version: 06-13

Note: The online Owner's Manual is the latest version available. Deviations between this manual and items specific to your vehicle may occur since Mercedes-Benz constantly adapts its vehicles to the latest technology and modifies design and equipment. Please note that this online Owner's Manual does not under any circumstances replace the printed Owner's Manual which is supplied with the vehicle.

Operating the auxiliary heating system

Important safety notes

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DANGER

If the exhaust pipe is blocked or sufficient ventilation is not possible, toxic exhaust fumes can enter the vehicle, especially carbon monoxide. This is the case, e.g. in enclosed spaces, or if the vehicle is stuck in snow. There is a risk of fatal injuries.

You should switch off the auxiliary heating in enclosed spaces which do not have an extraction system, e.g. a garage. If the vehicle is stuck in snow and you must leave the auxiliary heating running, keep the exhaust pipe and the area around the vehicle clear of snow. To guarantee a sufficient supply of fresh air, open a window on the side of the vehicle away from the wind.

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WARNING

When the auxiliary heating is switched on, parts of the vehicle, e.g. the exhaust system, can become very hot. Flammable materials, e.g. leaves, grass or branches, may ignite if they come into contact with hot parts of the exhaust system. There is a risk of fire.

Make sure no flammable materials come into contact with hot vehicle parts when the auxiliary heating is switched on.

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Turn on the auxiliary heating at least once a month for approximately 10 minutes. Otherwise, the auxiliary heating could be damaged.

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Make sure that the flow of hot air is not blocked. The auxiliary heating will otherwise overheat and switch off.

Your vehicle may be equipped with a hot-water auxiliary heater. Adjustment and operation of the hot-water auxiliary heater is done:

  • via the on-board computer and with the auxiliary heating button in the control panel more

  • with the auxiliary heating remote control more.

The auxiliary heating works independently of the engine and supplements the climate control system in the vehicle. The auxiliary heating heats the air in the vehicle interior to the temperature set.

If your vehicle is equipped with a hot-water auxiliary heater, the auxiliary heating also keeps the coolant warm. This way, the load on the engine is minimised and fuel is saved.

The heater booster function of the auxiliary heating supports the climate control system when the engine is running and the outside temperature is low.

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If the interior motion sensor more is primed and the auxiliary heating is switched on, it is possible that the interior temperature monitoring may cause a false alarm. In this case, either deactivate the interior motion sensor or switch off the auxiliary heating.

Heating time

The heating time operating the auxiliary heating when the vehicle is stationary without the engine running depends on the outside temperature.

Outside temperature

Heating time

above mbsymb6_inv_00d2.png5 corposwgl_2020.png

approximately 20 minutes

mbsymb6_inv_00d2.png5 corposwgl_2020.png to mbsymb6_inv_00d2.png15 corposwgl_2020.png

approximately 40 minutes

below mbsymb6_inv_00d2.png15 corposwgl_2020.png

approximately 50 minutes

You can then switch on the auxiliary heating again.

If you do not start the engine for a while, the total duration of heating is limited to a maximum of 120 minutes to protect the starter battery. Switching on the auxiliary heating is then automatically disabled. You can, for example, switch on the auxiliary heating without the engine running if the outside temperature is mbsymb6_inv_00d2.png20 corposwgl_2020.png a maximum of two times. If you try it again, the indicator lamps in the mbsymb1b_inv_0079.png button more flash alternately for approximately 2 minutes to signal switch-on interlock. The auxiliary heating cannot be switched on without starting the engine.

When the charge status of the starter battery is sufficient again, the switch-on interlock will be deactivated. To charge the starter battery, let the engine run. The engine runtime required to reach the necessary charge status depends on the outside temperature.

Outside temperature

Engine runtime

above 0 corposwgl_2020.png

approximately 10 minutes

0 corposwgl_2020.png to mbsymb6_inv_00d2.png10 corposwgl_2020.png

approximately 15 minutes

below mbsymb6_inv_00d2.png10 corposwgl_2020.png

approximately 20 minutes

Before switching on

Check the fuel level and top up if necessary.

The auxiliary heating is operated directly using the vehicle's fuel. The tank must be at least a quarter full to ensure that the auxiliary heating functions.

Switch on climate control more.

Set the temperature control to the desired temperature more.

Set the air distribution as required more.

Open the centre more and side air vents more and set them to the middle position.

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The auxiliary heating automatically switches to heater booster mode after the engine is started.

Operating with the button (control panel)

images/img866d180c91f04c0f35477e686f4a6f4a_1_--_--_JPG72.jpg

Switch the heater booster function on or off with the mbsymb1b_inv_00a2.png button more.

To activate the auxiliary heating system: press the upper section of the mbsymb1b_inv_0079.png switch for longer than two seconds.

The red indicator lamp in the button lights up. The auxiliary heating heats or ventilates the interior to the temperature that you have set. The blower switches to the first level.

When both indicator lamps in the button alternately flash for approximately 2 minutes, the switch-on interlock is active and the maximum total duration of heating has been exceeded more.

To switch off auxiliary heating: press the upper section of the mbsymb1b_inv_0079.png button.

or

Turn the key to position 0 in the ignition lock.

The red indicator lamp in the button goes out. The auxiliary heating operates for another two minutes and then switches off automatically.

Preselecting a switch-on time

Important information

You can use the on-board computer to define up to three switch-on times, one of which can be selected.

The yellow indicator lamp in the mbsymb1b_inv_0079.png button goes out after 30 minutes, if you:

  • have selected the switch-on time and

  • turn the key to position 0 in the ignition lock.

On-board computer without steering wheel buttons

Turn the key to position 2 in the ignition lock.

Press the mbsymb1b_inv_0079.png button.

The mbsymb1b_inv_0079.png symbol flashes in the display.

or

Press the mbsymb3_inv_0034.png menu button on the instrument cluster repeatedly until the mbsymb1b_inv_0079.png symbol flashes in the display.

Use the mbsymb5_inv_0066.png or mbsymb5_inv_0067.png buttons on the instrument cluster to select the switch-on time 1 to 3.

The switch-on time selected is displayed.

Wait 10 seconds for the standard display to appear.

The switch-on time is selected. The yellow indicator lamp in the mbsymb1b_inv_0079.png button lights up.

If you do not preselect a switch-on time, and --:-- is shown in the display, this means that the automatic switch-on mode is switched off. The yellow indicator lamp in the mbsymb1b_inv_0079.png button goes out.

On-board computer with steering wheel buttons

images/img1f8b1d4d351f15141846244e41e50c31_1_en_GB_JPG72.jpg

Turn the key to position 2 in the ignition lock.

Press the mbsymb1b_inv_0079.png button.

The Aux. heat submenu is shown in the display.

If no switch-on time has been selected, the selected switch-on time is highlighted or Timer off is highlighted.

You can also access the Aux. heat submenu via the Settings more menu.

Use the mbsymb5_inv_0057.png or mbsymb5_inv_0058.png button on the steering wheel to select the desired switch-on time.

Use the Timer off setting to deactivate automatic switch-on.

Press the mbsymb5_inv_0056.png button on the steering wheel.

The switch-on time is selected. The yellow indicator lamp in the mbsymb1b_inv_0079.png button lights up.

Setting the switch-on time

Use the same method to select a switch-on time as described in the "Preselecting a switch-on time" section.

On-board computer without steering wheel buttons

Press the mbsymb6_inv_0039.png reset button on the instrument cluster.

The hour display flashes.

Use the mbsymb5_inv_0066.png and mbsymb5_inv_0067.png buttons on the instrument cluster to set the hours.

Press the mbsymb6_inv_0039.png reset button.

The minute display flashes.

Use the mbsymb5_inv_0066.png and mbsymb5_inv_0067.png buttons to set the minutes.

The switch-on time is set and selected.

On-board computer with steering wheel buttons

Press the mbsymb5_inv_0026.png button on the steering wheel.

The display shows the Hours menu.

Use the mbsymb5_inv_0057.png and mbsymb5_inv_0058.png buttons on the steering wheel to set the hours.

Press the mbsymb5_inv_0026.png button.

The display shows the Minutes menu.

Use the mbsymb5_inv_0057.png and mbsymb5_inv_0058.png buttons to set the minutes.

Press the mbsymb5_inv_0056.png button.

The switch-on time is set and selected.

Operation with the remote control

Important information

You can switch the auxiliary heating on/off and set the operating duration using the remote control. You can use up to four remote control units on the vehicle. These must be synchronised for the receiver in your vehicle more.

The remote control has a maximum range of approximately 600 metres. This range is reduced by:

  • sources of radio interference

  • solid objects between the remote control and the vehicle

  • the remote control being in an unfavourable position in relation to the vehicle

  • transmitting from an enclosed space

Overview of the remote control

images/img1a1f33c8c74b899b351f190e366dde27_1_--_--_JPG72.jpg
mbsymb6_inv_003a.png Indicator lamp
mbsymb6_inv_003b.png To confirm settings
mbsymb6_inv_003d.png To switch the remote control on/off, set the operating duration or end or cancel settings

Indicator lamp : lights up in various ways to show different operating modes:

Signalling

Meaning

Lights up red

Remote control switched on

Data transfer

Flashes red

Auxiliary heating switched off

Lights up green

Auxiliary heating switched on

Flashes green

Change operating duration active

Flashes alternately red and green

Remote control in synchronising mode

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When the remote control battery is weak, indicator lamp mbsymb6_inv_003a.png flashes red rapidly. Replace the remote control battery more.

You can find further information on the lamp status in the "Problems with the auxiliary heating" section more.

Switching the remote control on/off

The remote control switches to standby mode after 10 seconds. Indicator lamp mbsymb6_inv_003a.png goes out.

To switch on: press and hold the mbsymb1b_inv_00dc.png button until indicator lamp mbsymb6_inv_003a.png lights up red.

If a connection between the remote control and the receiver in the vehicle has been established and indicator lamp mbsymb6_inv_003a.png:

  • flashes red, the auxiliary heating is switched off.

  • lights up green, the auxiliary heating is switched on.

To switch off: press and hold the mbsymb1b_inv_00dc.png button until indicator lamp mbsymb6_inv_003a.png goes out.

Switching the auxiliary heating on/off

Switch on the remote control.

To switch on: when indicator lamp mbsymb6_inv_003a.png flashes red, press the mbsymb5_inv_0062.png button.

During data transmission, indicator lamp mbsymb6_inv_003a.png lights up red.

When indicator lamp mbsymb6_inv_003a.png lights up green, the auxiliary heating is switched on.

To switch off: when indicator lamp mbsymb6_inv_003a.png lights up green, press the mbsymb5_inv_0062.png button.

During data transmission, indicator lamp mbsymb6_inv_003a.png lights up red.

When indicator lamp mbsymb6_inv_003a.png flashes red, the auxiliary heating is switched off.

Changing the operating duration

Switch on the remote control.

When indicator lamp mbsymb6_inv_003a.png flashes red, press mbsymb1b_inv_00dc.png and mbsymb5_inv_0062.png simultaneously.

Indicator lamp mbsymb6_inv_003a.png flashes green.

Press the mbsymb1b_inv_00dc.png button repeatedly until the desired operating duration is shown.

  • 20 minutes

    Indicator lamp mbsymb6_inv_003a.png flashes green twice.

  • 30 minutes

    Indicator lamp mbsymb6_inv_003a.png flashes green three times.

  • 40 minutes

    Indicator lamp mbsymb6_inv_003a.png flashes green four times.

Press the mbsymb5_inv_0062.png button.

During data transmission, indicator lamp mbsymb6_inv_003a.png lights up red.

If indicator lamp mbsymb6_inv_003a.png emits two long, green flashes, the selected operating duration is stored.

If no adjustment is made, indicator lamp mbsymb6_inv_003a.png flashes six times and the remote control goes into standby mode.

Synchronising the remote control

Press the mbsymb1b_inv_0079.png auxiliary heating button in the control panel more for longer than 10 seconds.

When you press and hold the mbsymb1b_inv_0079.png button, the red indicator lamp lights up in the button.

When the red indicator lamp in the mbsymb1b_inv_0079.png button flashes, the receiver in the vehicle is ready for synchronising.

Press and hold the mbsymb1b_inv_00dc.png remote control button until indicator lamp mbsymb6_inv_003a.png lights up red.

If there is an active connection between the remote control and the receiver, indicator lamp mbsymb6_inv_003a.png flashes alternately red and green. The remote control is in synchronising mode.

If you press the mbsymb1b_inv_00dc.png button again on the remote control after starting synchronisation, you will only synchronise this remote control unit with the receiver. Any other remote control units that were synchronised will be cleared. Indicator lamp mbsymb6_inv_003a.png flashes alternately red and green (very slowly).

Press the mbsymb5_inv_0062.png button on the remote control.

During data transmission, indicator lamp mbsymb6_inv_003a.png lights up red.

When remote control indicator lamp mbsymb6_inv_003a.png emits two long green flashes, the selected operating time is synchronised. The indicator lamp in the mbsymb1b_inv_0079.png auxiliary heating button goes out.

Switching the heater booster function on/off

images/img866d180c91f04c0f35477e686f4a6f4a_1_--_--_JPG72.jpg

The fuel-fired auxiliary heater heats the vehicle interior as quickly as possible while the engine is running.

The auxiliary heating automatically switches to heater booster mode after the engine is started.

If you switch off the engine without switching off the heater booster function, the system will be switched on the next time the engine is started (memory function).

Switch the auxiliary heating on or off with the mbsymb1b_inv_0079.png button more.

To switch on/off: press the mbsymb1b_inv_00a2.png switch.

If the indicator lamp in the button lights up, the heater booster function is switched on.

After switching off, the auxiliary heating operates for about another three minutes and then switches off automatically.

Replacing the remote control battery

../../../../global/pictures_mb/symb_achtung.png

WARNING

Batteries contain toxic and corrosive substances. If batteries are swallowed, it can result in severe health problems. There is a risk of fatal injury.

Keep batteries out of the reach of children. If a battery is swallowed, seek medical attention immediately.

../../../../global/pictures_mb/symb_baum.png

Environmental note

Batteries contain pollutants. It is illegal to dispose of them with the household rubbish. They must be collected separately and disposed of in an environmentally responsible recycling system.

Dispose of batteries in an environmentally responsible manner. Take discharged batteries to a qualified specialist workshop or to a collection point for used batteries.

If the indicator lamp on the remote control flashes red rapidly, the remote control battery is discharged. You should replace the remote control battery.

You need a battery of the type CR2430, which can be obtained at any qualified specialist workshop.

images/imga3f886a7c8522b55351f190e70461e20_1_--_--_JPG72.jpg

Remove battery cover mbsymb6_inv_003b.png using a suitable implement, e.g. a coin, by turning it anti-clockwise.

Check the seal on battery cover mbsymb6_inv_003b.png for damage and, if necessary, replace.

Remove old batteries mbsymb6_inv_003d.png.

Insert new, clean battery mbsymb6_inv_003d.png into the battery tray with the positive pole facing upwards. Use a lint-free cloth to do so.

Position battery cover mbsymb6_inv_003b.png so that mark mbsymb6_inv_003a.png on the raised area points between two recesses mbsymb6_inv_003f.png.

Remove battery cover mbsymb6_inv_003b.png using a suitable implement, e.g. a coin, by turning it anti-clockwise to the stop.

Check all the functions of the remote control more.

Problems with the auxiliary heating

Problem

Possible causes/consequences and > Solutions

The indicator lamp on the remote control flashes red rapidly.

The remote control battery is discharged. Data transmission is not possible.

Replace the remote control battery more.

The indicator lamp on the remote control flashes red and green in rapid succession.

There is no connection between the remote control and the receiver in the vehicle.

Change your position in relation to the vehicle, e.g. hold the remote control higher or to the side.

Move closer.

If you cannot establish a connection and the auxiliary heating is switched on, it can then only be deactivated using the mbsymb1b_inv_0079.png button more.

The indicator lamp on the remote control flashes red and green in rapid succession.

Several remote controls are being used at the same time.

Switch on the remote control again after a short while more.

The indicator lamp on the remote control flashes red and green in rapid succession.

The remote control is not synchronised.

Synchronise the remote control more.

The indicator lamp on the remote control slowly flashes red and green alternately.

The remote control is being synchronised.

Wait until the remote control synchronisation process is complete more.

The remote control for the auxiliary heating cannot be switched on.

The remote control battery is discharged.

Replace the remote control battery more.

The auxiliary heating cannot be switched on. The indicator lamps in the mbsymb1b_inv_0079.png button flash alternately for approximately 2 minutes.

The switch-on interlock is active and the maximum total heating duration has been exceeded.

Start the engine and let it run for the minimum runtime more.

The auxiliary heating switches off automatically and/or cannot be switched on.

The fuel tank is less than mbsymb6_inv_00d5.png full. The auxiliary heating switches off automatically.

Refuel at the nearest filling station.

Start the auxiliary heating several times until the fuel lines are filled.

The auxiliary heating switches off automatically and/or cannot be switched on.

The low-voltage protection system integrated in the control unit switches off the auxiliary heating because the on-board voltage is less than 10 V.

Have the alternator and battery checked.

The auxiliary heating switches off automatically and/or cannot be switched on.

The fuse is blown.

Replace the fuse; see the "Fuse allocation" supplement.

Have the cause of the blown fuse determined at a qualified specialist workshop.

The auxiliary heating does not switch on.

The heater is faulty.

Have the auxiliary heating checked at a qualified specialist workshop.

The auxiliary heating is overheated.

The coolant level is too low.

Check the coolant level and top up if necessary more.

Notes

Date of printing:

01/23/2022

Online Owner's Manual [In depth | Climate control | Operating the auxiliary heating system]

Owner's Manual version: 06-13

Note: The online Owner's Manual is the latest version available. Deviations between this manual and items specific to your vehicle may occur since Mercedes-Benz constantly adapts its vehicles to the latest technology and modifies design and equipment. Please note that this online Owner's Manual does not under any circumstances replace the printed Owner's Manual which is supplied with the vehicle.