Mysterious faults with instrument cluster

[320is]

Hello, I am a newbie for this forum, and also a proud new owner of 320is...

I bought my 89 320is with broken speedometer. I took out the instrument cluster, and changed the speedometer and after that the mystery started...

The left turn signal light in instrument cluster does not blink anymore. The actual lights are working properly... Right one is also totally working.



I took some measuerements, and the weird thing is: when the bulb is installed in cluster, there is no power at all. When removing the bulb, the power will be approx 10V and blinks as it should be... I have tested with many different bulbs..

Any experience of this kind of behaviour?


Ps. Sorry for harsh english...

[Cephas]

How tight are the grounds on the back of the cluster? There are two little (7mm?) brass nuts that can loosen over time. Start by making sure they are on there and are tight.

[320is]

Thx for hint, will test it next...

I also belive that it has something to do with groundings...