New member in need of some help saving a ZT-T Cdti

[SD1too]

Originally Posted by MGMarc

What provides the 12v K Bus voltage/signal?

Multiplex systems are not really my subject Marc, but my fundamental electrical knowledge tells me that it's probably from the BCU, but I could be wrong!

But all this theorising is not helping. I think you need to look at that pink* wire.

Simon
* Edit: According to my wiring diagram there is only one solely pink wire. The others have a tracer colour in addition.

[MGMarc]

Is it the pink wire which provides the K Bus it's power?

I'd like to diagnose this fault from the power source and follow along the wiring to connector C0289

Would somebody be able to provide me a wiring diagram which shows connector C0289?

[SD1too]

Originally Posted by MGMarc

Is it the pink wire which provides the K Bus it's power?

No, the pink wire is the K-bus connection between the ATC ECU and the BCU.

I'd like to diagnose this fault from the power source and follow along the wiring to connector C0289

I think you might be misunderstanding the principle of operation of the bus system Marc. It sends digital signals between multiple pieces of equipment using a single wire. As you only have a problem with the air conditioning showing 'error', the rest of the K-bus cannot be faulty.

Would somebody be able to provide me a wiring diagram which shows connector C0289?

Yes I can, if you don't mind sending me a suitable e-mail address by PM.

Simon

[MGMarc]

I have obtained relevant documentation and will have another go at fixing the K Bus issue tonight

Need to work out why the K Bus is at 0 volts

[trikey]

Check ecu for water, also if you have highline, water in the radio module will cause this!

[MGMarc]

I don't think I have high line as I have a radio cassette with no CD changer

I have 12.5v going to the ATC via the pink wire on pin 6

I have 0.4v going to the red/white/yellow wire on pin 6 going to the radio cassette

With both/either removed the fault still exists

Could do with a full colour wiring diagram for the MG but I'm starting to eliminate items now

[MGMarc]

Well I think that was two evenings I could have put to better use but hey ho, the header connector C0289 for the K Bus is located in the driver side kick panel NOT above the BCU as I previously thought and read

I've looked at the plug C0289 but can't see any pinout numbers, if you look at the picture I've marked the pin I'm interested in as it only has 3.8v it could well be the cause

I've got a feeling it's pin 14

[MGMarc]

Please ignore as pin 14 is linked to the instrument panel backlights

Thank you for everybody's help up to this point but I have started another thread as this one is getting muddled to my embarrassment through my own ineptitude

[SD1too]

Originally Posted by MGMarc

... through my own ineptitude

Rubbish! There is one thing you are not Marc, and that is inept. You are just finding your way around an unfamiliar part of the car which is far from straightforward. We've all been in the same boat, and will be again!

Simon

[klarzy]

The differance between ignorance and knowledge = asking the right questions + recieving the right answers.

The differance between knowledge and expertise is experiance.