Has anyone continued investigation of this problem?
I came across this thread recently through a search, after my car started blowing the #8 fuse-25A labelled heater blower. I think you guys were talking 126 dialect though, my 123 seems to be slightly different. It will blow a new fuse after 2-3 seconds, so it doesn't seem like it's a direct short. I have also proven the blower itself to be good on the workbench (20 amp fuse holds), and after consulting wiring schematics, unplugged the aux water pump but have not retested the circuit yet...
