What does the white wire clip to?

All orange wires lead to instrument dimmer controlled lamps

This is a "trick" circuit

Your headlight switch gets TWO power sources.

BATT to run the headlights ONLY, is unfused, and there is a breaker built into the light switch. This power runs nothing else, only the headlamps

BATT from the tail lamp fuse to the headlight switch This power goes through the switch, and runs park, tail, and feeds power TO the instrument lamp dimmer control

Power for the instrument lamps goes through the dimmer control and out on a TAN wire which feeds INTO the inst. fuse on the far end of your panel

In other words, for this fuse to have power.................

the tail fuse must be good and that circuit working

the light switch must be in park or head and be working

the dimmer control must be turned to the left to "brighten" the panel lights.

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After all the above is "true" the power TO the inst fuse goes through the fuse, and out to all dimmer controlled lamps ......on.......orange........wire