Alfa Romeo Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Hi everybody,

I bought my Alfa last week and after 3 days the first problem pop up:cry:

On monday I started the engine, enabled the rear window heater and set the ventilation to blow on the window and then went out to clean ice on the windows. When I went back in, there was no noise of fans... On the screen, it displays OFF and no way to switch to AUTO, ECON or to switch On the rear window heater, no reaction on any of the key.

Any idea what it could be?

At first, I checked at the fuses (in motor compartment and in front near driver door), without success.

Alfa mechanics told me it could be an electronic module (black box) that is located under the keypad command. I tried a second hand one but without success ( I cannot exclude that it is also broken, but I took it from a car that had only a problem of gearbox).
Did one of you had the same problem? Any diagramm where I could find out what voltage is expected where?

Thanks in advance for your tips and help.

Cheers

Greg
 

·
Administrator
GT 2.0 JTS
Joined
·
5,164 Posts
Functional description
The heated rear window relay J55 controls the simultaneous switching on of the demisting function of the rear window P55 , the heated windscreen P56 and the external rearview mirrors P60 and P61 .

(The control circuit of the heated rear window P55 passes through the power source/amplifier aerial P25 - See E3510 RADIO )

The supply line to the latter is also protected by the mirror demister fuse B16 . The relay J55 is supplied by the direct line from the battery through the fuse B33 .

An earth signal from the electronic Check device M45 - pin 10 of connector C - energizes the coil of relay J55 , so supply is sent to the resistors of P55 , P56 , P60 and P61 : this signal is enabled and suitably time-lagged by the device M45 .

An ignition-operated power supply (INT/A) for the Check device M45 reaches pin 9 of connector C through fuse F1 of junction unit B1 : pin 7 of connector C is earthed.

The device M45 gives enablement to the time-lagged switching on of the rear window when it receives the command from the on/off button - pin 11 of connector A - and at the same time the engine rpm signal is present - pin 8 of connector B, coming from the instrument panel E50 .

The enablement takes place when the engine speed is above 1000 rpm.

The button which switches on the heated rear window function is in the climate control panel H80 : the command is sent to the climate control unit M70 - pin 13 of connector C - from pin 9 through the serial line.

The control unit M70 is supplied - to pin 11 of connector B - from the ignition-controlled line (INT/A) of relay R1 protected by fuse F9 of junction unit B1 : pin 8 of connector C is earthed. From pin 9 of connector B of M70 , the command is sent to the Check device M45 - pin 11 of connector A.

With the function switched on, the Check device M45 sends back a signal - from pin 2 of connector B - to illuminate the led which indicates that the function is on; the signal reaches pin 11 of connector C of M70 and from there the controls H80 .
 

·
Administrator
GT 2.0 JTS
Joined
·
5,164 Posts
and this one


Functional description
Control unit M70 is supplied when the ignition is turned on (INT/A) at pin 11 of connector B from a line protected by fuse F9 from junction unit B1 .;

The power supply comes directly from the battery to pin 10 of connector C through fuse F17 of junction unit B1 and a line protected by maxifuse CENTR of B5 .

Pin 8 of connector C of M70 is earthed.

The outdoor temperature sensor is located on the left door mirror P60 : the sensor is connected to pins 1 and 7 of connector A of M70 .

Control unit M70 is also connected to sensors K87 (lower treated air), K88 (upper treated air) and K89 (passenger compartment air), which are connected to pins 3-5, 11-12 and 8-13 of connector A of M70 respectively.

Sensor K89 is fitted with a fan motor so that the temperature reading is not affected by the motionless and thus warmer air inside the facia: the motor is connected to the control unit via pins 10 and 12 of connector B.

Solar radiation sensor K90 is connected to pins 6 and 15 of connector A of M70 .

The air conditioning system is equipped with three activators for recirculation ( N82 ), air mixing ( N81 ) and air distribution ( N80 ).

Recirculation actuator N82 is controlled by control unit M70 , via pins 3 and 4 of connector B.

The air mixing actuator N81 is controlled from pins 1 and 2 of connector B from control unit M70 ; it receives a supply for control by potentiometer from pin 20, the reference earth to pin 14 at connector A, and sends a feedback signal to pin 16 of connector A.

The air distribution actuator N80 is connected from pins 7 and 8 of connector B from control unit M70 ; it receives a supply for control by potentiometer from pin 18, the reference earth at pin 2 of connector A, and sends a feedback signal to pin 17 of connector A.

An electronic governor operates fan N85 at different speeds: this receives a control signal from control unit M70 - from pin 2 of connector C - and converts it to a variable voltage signal that controls the fan.

Pin 1 of connector C provides a reference earth, pin 6 of connector C of M70 provides a speedometer signal.

Fan unit N45 is supplied when the ignition is turned on (INT/A) via relay J35 and fuse B65 .

Pin 4 of connector C of M70 receives a speedometer signal from instrument E50 .

A heated back window activation control - from pin 9 of connector B - is sent to control unit M45 ( See E3030 HEATED REAR WINDSCREEN AND DOOR MIRROR DEFROSTING . )

Pin 6 of connector B controls activation of the compressor ( See E6021 COMPRESSOR ENGAGEMENT ).

Climate control unit H80 communicates with control unit M70 via a serial connection line: from pin 13 of connector C of M70 to pin 9 of H80 .

The supply to the climate control unit H80 arrives directly from the battery. (maxifuse CENTR of B5 ) to pin 1, via fuse F18 of junction unit B1.

An ignition-operated power supply (INT/A) reaches pin 2 via fuse F5 of junction unit B1; pin 7 is earthed.

Climate control unit H80 is then connected - from pin 8. to ICS display E60 - pin 15 of connector B, via a special serial connection line.

Control unit M70 is equipped with a self-diagnostic system, that may be used by connecting to connector R10 : it receives signals from pin 13 of connector C of M70 through a serial connection line between control unit M70 and climate control unit H80 ; from here it is connected to the ICS display E60 .

Control unit H80 also receives other signals for the Trip Computer function of the ICS display: these signals are then exchanged with display E60 via the above serial line ( See E4090 NAVIGATOR ).
 

·
Administrator
GT 2.0 JTS
Joined
·
5,164 Posts
Fuses


The following fuses are connected to the ics below the steering wheel
fuse 7 ics system
fuse 4 ics radio
fuse 18 ics system battery

and there is a fuse on the back of the ics unit.

The fuses and relay for the rear demister are in the boot.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #5
Hi,

Thanks a lot for the quick response.

Problem seems to be fixed now.

After useless discussion and troubleshooting by Alfa (they wanted to sell me the electronic box under the keypad for CHF 600.-) I took my car back and went to a friend who is car's electrician. He is a Mercedes fan and blamed me to have bought an Alfa, but was very helpfull in troubleshooting.

First of all, a fuse was broken that I and Alfa didn't see (not clearly visible but you could see it with the ohmemeter). After changing the fuse, everything was working again until I tried to load my GPS.
--> problem was a short in the cigar lighter. I replaced it with a spare one I had and now everything is working!
When I remember my previous Alfa, the cigar lighther was not working but I never tried to understand the problem, maybe the previous owner had the same problem and disconnect it.
Is it a known weakness of the car?

@paul.o: Thanks a lot for your explanation, it helps a lot to understand the "electricity power plant" we have in our Alfa :). If you have the schematics to share, that would be greatly apreciated.
By the way, your Alfa is looking great, very nice color combination and the Zender kit fits the Alfa very well. Mine has the lght grey leather but my dream is to have the beige leather., maybe the next one:)

Thanks

Greg
 
1 - 7 of 7 Posts
Top