E28 Dashboard Issues

Google search points to the nicad batteries need replacing although I'm not convinced...

Symptoms, noticed when I picked it up from storage that the Fuel Consumption needle wasn't moving. It was working fine prior to it being put away 9 months ago. Then yesterday have noticed the Temp gauge wasn't moving either. Before I dismantle the dash to replaced the batteries is there anything else I should be checking. Are these needles really run off the battery power? I wouldn't have thought so hence me asking for a potential other reason.

Hope someone can help...


Thanks in advance

Mike