Problem with Stack unit

How interchangable are the stack units from the Mkl. My 2000 model 111S has a problem with the dials, both the rev counter and speedo are stuck in the 8 o’clock position. The engine warning light and oil light come on with ignition and turn off when engine running. I have tried a stack unit from an earlier Mk1 and nothing works.

HELP :slight_smile: