If you feel up to trying the diagnostics, you should read the article in DIY about evaluating engine controls. It describes how to do "Impulse Testing" with common tools (or an LED and some wire).
Apply the technique to pin 10 of the 16pin diagnostic connector (pass side rear of engine compartment). Read the codes. If you get some codes we will examine them. Eventually you will need the step chart that describes the various steps the top takes and checks off on. The code will usually tell you the last step done successfully.
Bosch Master, ASE Master, L1
33 years MB technician