Date:

March 17, 2014

Order No.:

V-B-83.70/06
83

Group:

SUBJECT:

MY-All, Models, 906.### #E up to 068530 with CODE H12 (Auxiliary heater - warm
water) and with CODE HZ5 (10 kW warm water auxiliary heater with timer);
906.### #N up to 527178 with CODE H12 (Auxiliary heater - warm water) and with
CODE HZ5 (10 kW warm water auxiliary heater with timer); 906.### #S up to
708567 with CODE H12 (Auxiliary heater - warm water) with CODE HZ5 (10 kW
warm water auxiliary heater with time
Stationary Heater, Auxiliary Heater And Heater Booster Service Information

There is a new procedure for the auxiliary heater using control unit A906 900 78 01 or new
auxiliary heater A906 830 59 00.
When replacing the auxiliary heater on Model 906 to N527178, S708567, E068530, the control
unit A906 900 78 01 or the new auxiliary heater A906 830 59 00 must be used.
Advantages to Customer
•
•
•

Reduced fuel consumption of auxiliary heater.
Reduce emissions from auxiliary heater.
Longer Service life - the complete heating duration on the starter battery is electronically
regulated by the new control unit based on outside temperature and starter battery
charge level.

Please inform your customers about the advantage of the new control unit and the changed
heat duration.
When the new auxiliary heater or the new control unit is installed, the operating period can no
longer be changed manually.
This information in the operator's manual of the vehicle under:
"Operation_/_Climate_control_/_Auxiliary_heater_/_Change_operating_period"
is no longer valid after the installation of the new auxiliary heater or the new
control unit. Please inform your customer about this.
This bulletin has been created and maintained in accordance with MBUSA-SLP S423QH001, Document and Data Control, and
MBUSA-SLP S424HH001, Control of Quality Records.
© 2014 Mercedes-Benz USA, LLC.
Mercedes-Benz Canada, Inc.
Dealer Workshop Services
www.MBUSA.com

All rights reserved. Reproduction or translation in whole
or in part is not permitted without authorization from the
publisher. Printed in U.S.A.

Heating Period
The heating duration of the auxiliary heater during idle operation without the engine running
depends on the outside temperature (see table) and the consumers that are switched on.
The auxiliary heater can then be switched on again as per the heating duration specified in the
table. If the engine is not started in the meantime, the complete heating duration is limited to a
maximum of 120 minutes for protecting the starter battery.
Switching on of the auxiliary heater is then automatically blocked. For example, the auxiliary
heater can be switched on a maximum of 3 times at an outside temperature of 23° F to ‑5° F
without the engine running.
If this is tried again, the indicator lamps
of the auxiliary heater button (Figure 1)
flash alternately for approximately 2
minutes, thus signaling the reclosing
lockout.
The auxiliary heater cannot then be
switched on without switching on the
engine. If the charge level of the starter
battery is not sufficient, the shift lock is
applied. All consumers that are not
required must be switched off so that
the start battery gets charged quicker
when the engine is running.
Figure 1. Auxiliary heater button

D83.70-1507-01

The engine running time for achieving the necessary charge level of the starter battery depends
on the outside temperature (see table) and the consumers that are switched on.
Ratio of outside temperature to possible
heating duration and possible number of
starts during idle operation

Outside
Temperature

Heating Period

Ratio of outside temperature to engine
running time for achieving the necessary
charge level

Starts

Outside Temperature

Engine Running
Time

Over 23° F

Approximately
20 minutes

6

Over 32° F

Minimum 10 minutes

23° F to 5° F

Approximately
40 minutes

3

32° F to 14° F

Minimum 15 minutes

Below 5° F

Approximately
50 minutes

2

Below 14° F

Minimum 20 minutes

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