Help! 1995 840ci.. Start car and gauges are dead.. Nothing lights up... If you rev the car up to 3k the tach kicks on and all the warning lights come on for 2 seconds including low fuel light and red overheat light. Then they go off and tach stays on... Fuel and temp gauge don't work at all.. Speedo and odometer work fine. Is this a SI battery issue in the cluster? Don't think it's the voltage reg cuz no flickering in lights or anything.
This one could get messy real quick. You will need to start with the basics check fuses for the cluster make sure none are blown. There are a few things that could cause the cluster to do this. It's the cluster itself, BEM (body electronics module) that communicates the data to the cluster. The wiring from the cluster to the BEM. And powers and ground to either modules. Also yes a alternator can also cause this but just because you don't see flickering lights doesn't mean the alternator is good. I would check voltage at the battery with the vehicle running and see if its around 13v-15v. If its below that it's not charging but if it's above that then you have a bag regulator on the alternator and the computer on the vehicle will go into protection mode and shut down.