Retrofit PTC heater booster

AN83.70-S-0007E

Retrofit PTC heater booster

09.10.2019

Model

447.6/7

with code ZU7 (National version for Canada)

Model

447.6/7

with code ZU8 (National version for USA)

Model

447.6/7

with code ZU9 (National version for Mexico)

Model

448

Modification notes

08.10.2019

Work procedure revised.

Whole document.

3

Plug-in connector

4

Bolts

5

Cover

6

Electrical connector

N33/4

PTC heater booster control unit

1

Ground cable

2.1

Ring cable lug with nut

K40/11

Firewall fuse and relay module

1.1

Ring cable lug with nut

2.2

Ring cable lug with nut

N33/4

PTC heater booster control unit

1.2

Ring cable lug

A1

Pin terminal

W1/7

Cockpit ground point

2

Positive line

Topical note

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-0001-01A

Topical note

Notes on carrying out repair work in the vehicle interior

AH68.00-N-0001-01S



Remove

1

Detach ground line of on-board electrical system battery.



AR54.10-S-0003E

2

Remove left cover under instrument panel.



Model 447.6/7 with code LC7 (Illumination for front footwell), model 448

AR68.10-S-1500E

3.1

Remove center console.

Model 447.6/7, 448.7 with code FF1 (Center console with stowage compartment), model 448 with code FG0 (Luxury center console with roller blind)



Model 447.6/7, 448.7 with code FF1 (Center console with stowage compartment) except code FG0 (Luxury center console with roller blind)

AR68.20-S-2000E



Model 448
with code FG0 (Deluxe center console with roller shutter door)
except code FF1 (Centre console with stowage compartment)
except code FG6 (Center console with cooling compartment)

AR68.20-S-2000EA

3.2

Remove center console.

Model 448.8
with code FG6 (Center console with cooling compartment)
except code FF1 (Centre console with stowage compartment)
except code FG0 (Deluxe center console with roller shutter door)



AR68.20-S-2000CH

 To do so, remove center console, pull toward rear and place outside of working area. Do not disconnect electrical connectors.

3.3

Remove trim from vertical strut.

MODEL 447.6/7 except CODE FF1 (Center console with stowage compartment) except CODE FF2 (Center console with 1-DIN slot) except CODE FG0 (Luxury center console with roller blind)



AR68.00-S-1500E

4

Remove connector coupling (3) from device installation frame.

5

Remove electrical connector (6) from heater box.

 Do not disconnect electrical connector (6).

6

Remove screws/bolts (4).

 Screws (4) are no longer required.

7

Remove cover (5).

 Covering (5) no longer needed.

8.1

Remove right cover below the instrument panel.

Model 447.6/7 with code LC7 (Illumination for front footwell), model 448



AR68.10-S-1520E

8.2

Remove trim in right footwell.

Model 447.6/7 except code LC7 (Front footwell illumination)



AR68.30-S-4030E

9

Remove nut of cockpit ground point (W1/7).



Install

10

Retrofit PTC heater booster control unit (N33/4).


Install PTC heater booster control unit (N33/4) carefully and uniformly into device installation frame.
This prevents damage.

 When doing so, operate brake pedal. Ensure that PTC heater booster control unit (N33/4) is seated correctly in installation frame of device.

11

Fasten PTC heater booster control unit (N33/4) using screws (4).

 To do so, use new screws (4) from the parts kit supplied.

12

Attach electrical connector (6) to heater box.

 Check retaining clips for damage.

If the retaining clip is damaged.



Replace damaged retaining clip.

13

Connect connector coupling (3) to PTC heater booster control unit (N33/4).

14

Route ground line (1) and positive line (2), as shown, into instrument panel.


Do not kink ground line (1) and positive line (2) and ensure routing is without any chafes.
This prevents damage.

15

Fit ring cable lug with nut (1.1) of ground line (1) to PTC heater booster control unit (N33/4) and fasten.

 Nut, wiring harness to PTC heater booster

*BA54.18-N-1001-02A

16

Fit ring cable lug with nut (2.1) of positive line (2) to PTC heater booster control unit (N33/4) and fasten.

 Nut, wiring harness to PTC heater booster

*BA54.18-N-1001-02A

17

Fasten ground line (1) and positive line (2) in sections to the electrical wiring harness fitted at the factory using cable ties.

If necessary,



Strap down excess lengths of ground line (1) and positive line (2).

18

Remove cover from firewall fuse and relay module (K40/11).

19

Fit ring cable lug with nut (2.2) of positive line (2) to pin terminal (A1) of firewall fuse and relay module (K40/11) and fasten.



Assignment of right footwell firewall fuse and relay module

Model 447.6/7 except code XM0 (Facelift), model 448

GF54.15-S-1256-39TRA



Assignment of right footwell firewall fuse and relay module

Model 447.6/7 with code XM0 (Facelift)

GF54.15-S-1256-39TRF

 M6

*BA00.10-N-1002-01A

20

Install cover at firewall fuse and relay module (K40/11).

21

Fit ring cable lug (1.2) of ground line (1) to cockpit ground point (W1/7).

22

Attach nut of cockpit ground point (W1/7).

 M6

*BA00.10-N-1002-01A

23

Install in the reverse sequence.

 Operation steps 8, 3, 2, 1.

24

Supplement special equipment via Vehicle Documentation (VeDoc).

 Designation of affected special equipment: code HZ0 (Electric auxiliary heater).

 Attach note "PTC heater booster retrofitted as per AN83.70-S-0007E" under field organization texts to DG 83.

25

Connect diagnostic system and read out fault memory.



AD00.00-S-2000-04E

 Do not yet remove vehicle diagnosis system.

If existing faults are stored,



Erase the fault memory.

26

Perform SCN coding on signal acquisition and actuation module (SAM) control unit (N10/1).



AR54.21-S-0015E

 Under the menu item "Control unit adaptations", follow the instructions for "SCN coding".
Do not yet remove vehicle diagnosis system.

27.1

Run SCN coding on air conditioning system control and operating unit (KLA-V&KLA-H) (S98).

Model 447.6/7
with code ZU7 (National version for Canada)
Model 447.6/7
with code ZU8 (National version for USA)
Model 447.6/7
with code ZU9 (National version for Mexico)
Model 448.7



AR54.21-S-0015E

 Under the menu item "Control unit adaptations", follow the instructions for "SCN coding".
Do not yet remove vehicle diagnosis system.

27.2

Run SCN coding on automatic air conditioning (AAC) control unit (N154).

Model 448.8



AR54.21-S-0015E

 Under the menu item "Control unit adaptations", follow the instructions for "SCN coding".
Do not yet remove vehicle diagnosis system.



Check

28

Check PTC heater booster control unit (N33/4) for proper operation.

 Model 447.6/7
with code ZU7 (National version for Canada)
Model 447.6/7
with code ZU8 (National version for USA)
Model 447.6/7
with code ZU9 (National version for Mexico)
Model 448.7
See in vehicle diagnosis system under "Air conditioning system control and operating unit (KLA-V&KLA-H) (S98)" at selection "PTC heater booster control unit (N33/4)" in "Actuations" tab.

 Model 448.8
See in diagnostic system under "Automatic air conditioning (AAC) control unit (N154)" when selecting "PTC heater booster control unit (N33/4)" in the "Actuations" tab.

29

Remove vehicle diagnosis system from vehicle.

 Headless screws/bolts: screws/bolts and nuts, coarse-pitch thread

Number

Designation

8.8

10.9

BA00.10-N-1002-01A

M6

Galvanized

Nm

9

13

Phosphated

Nm

9

12

 Headless screws/bolts: screws/bolts and nuts, coarse-pitch thread

Number

Designation

12.9

BA00.10-N-1002-01A

M6

Galvanized

Nm

16

Phosphated

Nm

14

 Wiring harness

Number

Designation

Model 447, 448

BA54.18-N-1001-02A

Nut, wiring harness to PTC heater booster

M6

Nm

8

M8

Nm

16

Parts ordering note

Part no.

Designation

Quantity

KG 99

PTC heater booster parts kit

1