Hi, yeah I've had all the dash and instruments out, nothing been touched in there other than where someones cut the original wires for the stereo.
From what I can the the red/white is the power for the dash lights and have traced it all the way back to the Becm, the Becm is putting out a voltage to the red/white but it's not getting to the dash lights. I put an ammeter between the red/white at the Becm and the red/white at the stereo and they all came on with the lights but the dim control doesn't work which makes me think the red/white goes from the Becm to something else which controls the brightness then onto the dash lights, and the fault lies with either the dimmer control assy or the wire/connections from that to the dash lights. But I may be a mile of which is why the wiring diagram should help!
Hope that makes sense.