Sharan Body Control Module

[daveandsharan]

I have a 2004 115SE Sharan.

 

The radio and heater control panel don't work any more. Everything else works OK.

 

After checking all the fuses and substituting another radio (same problem), I gave up and paid for a diagnostic scan at my local independent.

 

Their view was that it was probably a problem associated with the Body Control Unit which required dash removal to access. They think it might be a broken wire in the harness.

 

My question is, what else does this BCM control? If everything else works OK, I guess a broken wire is an accurate diagnosis.

 

If the BCM was faulty, what else would be affected?

 

If I need a new BCM, do they need to be programmed to my car? I can see

[Mirez]

I have a 2004 115SE Sharan.

 

The radio and heater control panel don't work any more. Everything else works OK.

 

After checking all the fuses and substituting another radio (same problem), I gave up and paid for a diagnostic scan at my local independent.

 

Their view was that it was probably a problem associated with the Body Control Unit which required dash removal to access. They think it might be a broken wire in the harness.

 

My question is, what else does this BCM control? If everything else works OK, I guess a broken wire is an accurate diagnosis.

 

If the BCM was faulty, what else would be affected?

 

If I need a new BCM, do they need to be programmed to my car? I can see

[daveandsharan]

Thank you Mirez for your helpful reply.

 

With respect to the radio, the alarm LED flashes with the ignition off and the buttons light up with the sidelights on. If I press the "ON" button, I see a rapid flash across the screen, and that's it.

 

I measured the pins as follows: 1= 3v ign off; 2= spare; 3= 11v ign on: 4= 12v ign off; 5= 1.5v ign off; 6= 8v with sidelights on; 7= 12v ign off; 8= capacitive earth, ie. a full swing of the needle then a slow fall back to a mid point.

 

Although the voltages are present and correct, perhaps there is insufficient current?

 

WRT the heater control unit. It is not climate controlled but three dials with three buttons below.

 

Firstly, none of the fascia illuminates with the sidelights on.

 

Only the middle blower dial operates the blower motor on all four speeds (so hedgehog OK?) The other dials are for (1)aircon on and (2) hot and cold.

 

I saw a previous response of yours re pin voltages on the back of this unit and they appear OK. Which makes me think the insufficient current might be the issue.

 

 

From your reply, I guess the good news is that because everything else works, the actual BCM is probably OK.

 

I am puzzled by the fact the radio and heater control unit both stopped working at the same time. I can't understand the relationship between the two.

 

I might try to connect a good earth to pin 8 of the radio to see if this makes any difference. I wonder if both items share a common earth?

 

Grateful for any further thoughts you might have,

 

Dave

[Mirez]

Humm, well remember I'm a Ford man so accept the info may be wrong but here are the results you have against what I would expect:

 

1= 3v ign off;

This is the GALA Signal (Ford VSS) - Basically a speed signal so suprised to see a voltage here with the ignition off

2= spare;

Correct this is the Telephone Mute input on vehicles with telephone provisions. 2V+ will mute the radio.

3= 11v ign on:

Interesting. This is the K-Line for diagnositcs, its a signal line and normally sits at about 5V so 11V isn't really expected.

4= 12v ign off

Correct Memory feed from F31

5= 1.5v ign off

Incorrect. This is the SAFE pin which the radio requires to know when its attached to a vehicle. 12V from F32 (5A) would be expected here at all times.

6= 8v with sidelights on

Correct this is the illumination feed and the voltage will vary with the dimmer

7= 12v ign off;

Correct. This is the primary power from F30

8= capacitive earth

With the radio in or out of circuit?

 

F32 also supplies a feed to the heater controller on the black connector Pin70 (Red/White) so its certainly worth rechecking F32 in the fuse box, it should be the 6th in horizontal fuse.

Edited October 17, 2010 by Mirez

[daveandsharan]

Hi Mirez,

 

Great info many thanks.

 

All measurements were taken on the actual pins with the radio out of the car.

 

As you suggest I will check F32 again with a multimeter. Previously I just looked at each and every fuse! I'm not sure the fuse "map" on the fuse box can be relied upon.

 

Then again this also assumes the Sharan and Galaxy are alike in this respect. Worth another check nevertheless.

 

Thanks again,

 

Dave

[daveandsharan]

My problem is solved!

 

Despite all the helpful and detailed information, (many thanks to Mirez) I wasn't able to find any obvious faults, so I left it in the hands of my local independent.

 

As diagnosed on the initial scan, the fault was a broken wire in the loom between the BCM and the radio and heater control unit. Apparently there is a common live feed.

 

Now repaired at a cost of two hours labour to remove dash to gain access. Everything working again. Nice to have warm air on these cold mornings!

 

I note there are similar problems being reported, with non-working unrelated electrical items.

 

Hope this helps someone out there,

 

Dave

[Mirez]

Glad its resolved, can you now measure the voltage on pin 5 - see if its still at 1.5v or is now at 12V :)

[daveandsharan]

Yes Mirez, it is 12v constant now.

 

I guess with hindsight I could have connected a lead between the output of F32 and pin 5 on the radio. May have been a cheap fix.

 

However, if the BCM "talks" to the ECU (?) I guess it might have interrupted the "conversation" ?

 

Well we live and learn and all is well now,

 

Dave