Clock won't adjust - '92 100S

[Karl Nitz-GKN001 <Karl_Nitz-GKN001@email.mot.com>]

        After having read through the instructions in the owner's 
     manual, I still can't seem to adjust the time on the dashboard 
     clock.  According to the manual, all I need to do is hold down the 
     dash-light dimming knob/button and then the clock will begin to 
     advance. 
        If I hold down the button, nothing happens.  The clock runs 
     fine, but it won't adjust.
     
     Has anyone out there had this problem and what was your solution?
     
     Regards,
     Karl H. Nitz
     gkn001@email.mot.com
     
     '92 Audi 100S, 78K miles, clock is set 50 minutes fast
     '97 Chrysler Sebring LXi, 34K miles, wife's "German" car
     '81 VW Rabbit Diesel, 198K miles, 40MPG Daily Driver
     '86 Kawi ZL600 & '85 Honda VF500F, in hibernation