I divide the headlite switch into two circuits, a circuit breaker for the headlamps, and fuse circuit for the dash lites--tail lites, whatever. I usually suspect the longest circuit first, brown wire from the headlite switch to the tail lites.
I fixed a problem similar to this a few weeks. A GM vehicle, different year and model than yours. It was dead short to ground on that brown wire circuit that goes to the tail lites. It would blow the fuse just as soon as you turned on the headlite switch. I took the connector loose at the headlite switch and at the rear, then used a testlite connected to voltage, touched it to the brown wire, the lite came on. So I knew where the short was, it didn't blow the fuse because the testlite controlled the load on the circuit. I can't say if you have the same problem.
Saturday, February 14th, 2009 AT 2:07 PM