[johnsonace]

Symptoms seem to be the same as OP's. The odometer & clock light up when the headlights come on. When the lights are turned on manually with the ignition off, result is the same. Turning the dimmer has no effect. When the knob is rotated past the detent to light the interior, all the dash & IP lights come on bright. Guessing that the dimmer is bad. Suppose it can be by-passed?
Many thanks,