Zitat von sandwich;78735The fuel low warning light is also out by the way. Not sure if that makes any difference but thought I had better mention it.
The reserve light is switched by the EKM. If the fuel tank contents on service menu 7 of the MID read below 10 liter the light should be on. If it should but isn't, the problem is very likely related to your cluster issue.
ZitatDoes the info go to the MID from the same source that transmits it to the cluster? eg Does all the info go from the EKM to the MID and cluster?
Both cluster and MID receive their information from the EKM, although not over the same bus. The MID is connected over the I-bus whereas the cluster has its own dedicated serial link. Nevertheless MID and cluster share the same data source, so if one functions properly the problem is unlikely in the EKM. Data corruption in the path that differs from that from the MID - EKM serial transmitter/receiver, wire and cluster serial transmitter/receiver - is also unlikely. In the digital world it usually either works completely, or not at all. Since the speedo functions normally, you can rule that out.
External power supply issues are also unlikely. In that case the speedo and several other warning lights wouldn't work either. The instrument cluster test would fail too. None of this is the case.
The erratic behavior which eventually lead to dead gauges may be caused by bad solder joints - as you already suggested in your first post. But it's unclear to me why the instrument cluster test then works properly. As far as I know the cluster test is just a test routine of the same microprocessor that reads the data received from the EKM.
Do trip and odometer still function properly? In case of an automatic transmission, are gear and program still displayed in the cluster?
Just wondering... Does the handbrake light work properly and does it come on for approximately 3 seconds when you turn the ignition on - even with the handbrake not applied? (the handbrake light is also provided by the EKM).