dashboard indicators not working

[loai]

Hi,
I just bought a used 93 volvo 850 GLT. I had a new engine installed and the car runs great. However, the speedometer, Fuel tank indicator and termperature indicator are all not working (dont move at all from low position). The only idicator that works is the rpm indicator (All digital indicators are working fine). Do you know what is causing this and how to fix it ?
Thanks for your reply.