Can anyone tell me where the bulb failure module is located on a Sierra (3 door cossie) and whether it's likely to be the culprit for the disco lighting problems I'm experiencing?

The display panel has shown a persiatant fault, which does exist, with the driver's dipped beam for some time; I checked the earth next to the light and it was good, checked the relay and it's fine, can't get to the bottom of it.

Now I'm seeing intermittant warnings for the brake lights which seem to be fine, side and tail lights that come and go; it's driving me mad and I really should get to the bottom of it seeing we're in midwinter!

Any ideas?

CheeRS,
Iain