Flap Control

Here is a survey of sliding control lever and flap positions. Requirements: engine running and vacuum built up.

Heating is only effective when the upper sliding control lever is pushed to the right and the lower control lever is positioned at an air distribution symbol.

Upper lever controls heater valve "W" and coritr. flaps " B"

928 Heater Control Valve

Upper lever controls heater valve "W" and coritr. flaps " B"

Both levers must be on right end for defrost

Lower lever controls air distribution, turning on AC and opens heater valve "W" in "DEF" pos.

" open since Ch.No.928 810 1535

. manual regulation since Ch No. 928810 1884

' only when upper contr.lever is far left

Control flaps closed (max. cooling effect)

E — Center nozzle flap Circulating air flap

W— Heating valve

E — Center nozzle flap Circulating air flap

W— Heating valve

Both levers must be on right end for defrost

Lower lever controls air distribution, turning on AC and opens heater valve "W" in "DEF" pos.

" open since Ch.No.928 810 1535

. manual regulation since Ch No. 928810 1884

' only when upper contr.lever is far left

Control flaps closed (max. cooling effect)

Vacuum System Layout

Defrost Flap944 Turbo Porsche Thermo Switch
CEL power rail

1 - Relay XVIII (extra fan)

3 - Relay XXII (defrost)

5 — Air distribution control lever

7 — Thermo bimetal switch

A — Coolant temperature switch 95 °C B — Frigen temperature switch 52 °C (on riser tube at top) C — Microswitch (air distribution control lever) D — Thermo switch (icing-up protection for evaporator between -1 °C and + 3°C) E — Low pressure switch (Frigen 2.2 bar on side of liquid tank) K — A/C compressor clutch

Porsche 928 Clutch

T3 - Evaporator temperature switch (—1 °C to +3 °C)

R2 — Defrost relay

Tb U

— Thermo bimetal switch

— Program control lever

— Microswitch

— Low pressure switch for Frigen (2.2 bar}

KM — Compressor magnetic clutch ML — Solenoid air valve

Speed relay XI is connected via term. 31 b with control unit term. 16 of the ignition system. 16 of the ignition system. The electronics of relay XI open the relay contacts when the engine speed is higher than approx. 5500 + 100 rpm, through which the compressor clutch is switched off to prevent excessive loads on the compressor.

The A/C compressor is also switched on in the "DEF" program control lever position, in order to remove moisture from the incoming fresh air via the evaporator. This reduces fogging of the windshield with moist fresh air.

Flap Control

Tj — Temperature switch — coolant (95 °C) T2 — Temperature switch — Frigen (52 °C) T3 — Temperature switch — evaporator

(-1 °C to +3 °C) R, — Extra fan relay R2 — Defrost relay Ra — Blower relay Z — Extra fan

Tb — Thermo bimetal switch Lv — Program control lever M — Microswitch

D — Lower pressure switch — Frigen (2.2 bar) KM — Compressor magnetic clutch ML — Solenoid air valve K — Compressor switch F — Solenoid valve r

AUTOMATIC

ECOT ECOAT

The automatic air conditioner will maintain a set (preselected) inside temperature, regardless of the outside temperature.

This is accomplished by constant heating and cooling, and is monitored by outside and inside temperature sensors.

An electric motor (on left side of the air conditioner box or right side for RHD cars) operates the heating flaps (open/closed) depending on the program selected with the control switch.

Air conditioner compressor cooling of the passenger compartment is only possible from "AUTOM." program position on.

Cooling will only be in accordance with the instantaneous outside temperature in "ECO" position, since the compressor is not switched on.

Components: Inside sensor with blower (in instrument panel).

Outside sensor (in alternator cooling hose). Control switch with temperature selection lever (reacts to a potentiometer). Control switch with program selection lever.

Motor on left side of air conditioner box (right side for RHD cars).

6 solenoid valves underneath the air conditioner box control vacuum to the vacuum units of the air flaps.

Note: In temperature selection lever position 18 (left stop) there is only

(since 1982 models) cooling, no heating — max. cooling.

In temperature selection lever position 30 (right stop) there is only heating, no cooling — max. heating.

This test plan can be used to check the function of the M 563 automatic air conditioning system and to pinpoint any faults quickly.

Proceed step by step when checking and make sure that each test is performed with the correct tester at the correct test point. A wiring diagram is also provided.

Only an ohmmeter and a test lamp are required for testing.

Where What Is:

Test

Test Point

Page

Power supply

A 1-5

9

Ground connections

A 6-8

9

Sensors

B

11

All sensors

B 1

Inside sensor

B 2

Inside sensor blower

B 2a

Outside sensor

B 3

Temperature potentiometer

B 4

Control switch removal

B 4a

Control unit/flap function

C

19

Operating motor

C 1

Solenoid valves

C 2

Flap function

C 3

Cold start interlock

D

25

with cold engine

D 1

with warm engine

D 2

Compressor magnetic clutch

E

27

Test box for operating motor

F

28

Flap program

G

29-31

Wiring diagram up to 1983

H

Control switch n Temperature control

No 921 wire harness

M563

Control switch

No 921 wire harness

1983 Porsche 930 Wiring Harness

n Temperature control

A- Water valve + mixture flap

B- Bypass flap

C- Footwell flap

Plug connector M-piri

No 181 wire harness lug connector,( 1-pin

A- Water valve + mixture flap

B- Bypass flap

C- Footwell flap

D'E- Center nozzle ventilation 1st/2nd Step a jf| Motor- 'rt-pOI

Plug connector M-piri

No 181 wire harness

Meaning of codes in wiring diagram: B1 — Control switch plug, small (10 pins)

52 — Control unit plug, large (12 pins) M — Center nozzle switch

A) POWER SUPPLY (Test Lamp)

The electric part of the air conditioner is supplied with power from term. 15 (ignition lock) via fuse no. 9.

Testing

Remove CEL cover; remove both side trim panels on center console. Turn on the ignition.

Power To:

3. A 6-pin flat male plug (3) seen on right side of the center console: term. 1 (black/white).

4. On control switch plug (B1) term. 4 (black/white) and term. 5 (black/white). Plug is accessible only after removing the switch unit. Test point 5 only has to be performed, if the flap positions are not changed when operating the program control lever.

5. Term. of Plug With Program Lever in Position

3

B1

OFF

10

B1

OFF

4

B2

OFF

5

B2

OFF

13

B2

ECO/AUTOM/AV/DEF

14

B2

ECO/AUTOM/AV/DEF

15

B2

ECO/AUTOM/AV/DEF

11

B2

DEF

7

B1

ECO/AUTOM/AV

8

B1

ECO/AUTOM/AV

6

B1

ECO/AV (operate temperatui

8

B2

AUTOM/ECO

9

B2

AUTOM/AV/DEF V

12

B2

7. Control switch plug (B2) term. 2 and 3 (each brown). Plug is accessible from the left side.

8. Control unit plug (S2) term. 3 (brown). S2 is the large 12-pin plug; right plug connection on the control unit.

M 563

Control switch

Temperature control

No 921 wire harness

M 563

Control switch

No 921 wire harness

M563 Porsche

Temperature control jL

A- Water valve + mixture flap

B" Bypass flap

C- Footwell flap

F- Defroster flap

14-pin

181 wire harness

A- Water valve + mixture flap

B" Bypass flap

C- Footwell flap

D/E- Cenier nozzle ventilation 1st/2nd Step

F- Defroster flap jL

14-pin

181 wire harness

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