Those switch units are all miniture relays and integrated circuits. Mine has fried completely and Isuzu want $500 for a new one, but then I have a right hand drive.

It sounds like the relevant relay has fried in the drivers door unit. You can check that its not a broken wire by temporarily running one and seeing if it works. There is a downloadable wiring diagram in the downloads section that should tell you which wires to splice.

Failing that, do you have another member near you who let you try their switch unit?