Preface: I've studied the schematics in the Triumph shop manual and the Haynes manual for the Classics models and could not come up with a reason for the symptoms described.
The schematic in both manuals is for a European version with a headlight switch.
There have been a minimum of two European versions of the Classics wiring harness and neither schematic in my manuals is identified as an earlier or later version.
Mutato is a 2000 US model with the later version harness and no headlight switch.
Testing: I removed the fuses, one at a time, from my bike to try and duplicate the symptoms.
With the fan/turn signal fuse removed, both emergency flashers and turn signals were disabled. All other lighting circuits worked normally.
With the tail/stop light fuse removed, the flashers/signals functioned normally but the instrument illumination circuit was inoperative. All other lighting circuits worked normally.
The symptoms described in the original post could not be duplicated.
Conclusions: The symptoms described are associated with an early wiring harness version and probably only with a US version.
The failure of the fan fuse is probably the result of a defective fan or the installation of a 10 Amp fuse instead of a 15 Amp fuse in the #4 fuse position.
Hypothesis: There is a miswire in the right handgrip connector such that the jumpers used to bypass the Euopean headlight switch are either cross-connected or shorted to each other in such a way that power is being transferred from one circuit to the other. The behavior described in the frst post of this thread would seem to indicate this.
According to the schematic in the shop manual, it appears that on the US version there should be a jumper from pin 3 to pin 1 and a second jumper from pin 8 to pin 6 of the connector.
It should be possible to verify this by swapping in a later model grip and switch assembly.
I cannot verify the jumper configuration on my 2000 model at this time.
[ This message was edited by: jimmyj900 on 2006-11-05 13:46 ]