Hi ve39,
basically the E32 has the same probs with that as the E34. So first of all, check the fuses, change them even if they seem to be o.k.
Use a mutlimeter and check if there is power on the light cables at the bulb sicket.
Next thing -if that does not bring any result-as usual: soldering LKM, mustard relay.
Also check if the wire connections to the bulb holders are corroded. Sometimes they look nice, but underneath the plastic the core is compeltely oxydized.