Audi Q7 2007 Repair Manual page 93

Design and Functionality of the Auxiliary Air Heater Heating Ele‐
ment - Z35-
♦ On vehicles with an electric air heater, the air is supplied with
heat energy after leaving the heat exchanger of the A/C unit if
there is a request from the Climatronic Control Module - J255-
front A/C display control head and no shut-off conditions are
stored in the engine control module. Refer to Wiring diagrams,
Troubleshooting and Component locations and use the Vehi‐
cle Diagnostic Tester via the "Guided Fault Finding" function.
♦ To achieve the maximum heat output at the Auxiliary Heater
Heating Element - Z35- , the heating element has to be cold
and the Generator - C- may not be overloaded, or still have
sufficient output reserves. If the Generator - C- is overloaded,
the respective engine control module partially or completely
switches off the Auxiliary Heater Heating Element - Z35- . Use
the Vehicle Diagnostic Tester via the "Guided Fault Finding"
function (for the engine installed in the vehicle).
♦ The Auxiliary Heater Heating Element - Z35- has several lay‐
ers of resistance elements -A-, which together reach a heat
out of approximately 1200 W (1500 W from MY 2013 as a
running change). When level "1" is activated, the current is
Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not
guided via contact "1" in the connector -F- to the heating ele‐
permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability
ment -B-. It then flow over both resistance elements-A- to the
with respect to the correctness of information in this document. Copyright by AUDI AG.
connected heating element -D- connected to the ground con‐
nection -E-. When level "2" is activated, the current is guided
via the contact "2" inside the connector -F- to the heating ele‐
ments -C-. It then flows over the four resistance elements
-A- to the connected heating elements -D- on the ground con‐
nection -E-.
♦ The Auxiliary Heater Heating Element - Z35- is designed so
that, when switched on, no current greater than 40 A /45 A
flows via the contact "1" inside the connector-F- and no current
greater than 80 A/90 A flow via the contact "2" inside the con‐
nector -F- (the resistance of the resistance heating element
-A- increases and the current decreases immediately after the
switching on).
♦ To reach the maximum heating output of approximately 1200
W (1 x 400 W and 1 x 800 W) or approximately 1500 W, the
resistance heating elements temperature must be low and the
Generator - C- must deliver enough current.
Auxiliary Heater Heating Element - Z35- , Checking
– Switch off ignition.
– Remove the glove compartment. Refer to ⇒ Body Interior;
Rep. Gr. 68 ; Storage Compartments and Covers .
Heating, Ventilation and Air Conditioning - Edition 04.2013
8. Components Actuated by A/C System, Electrical Test
Audi Q7 2007 ➤
87