On off switch karcher 610 what connections go to the mains wires I have white to No 1 and black to No 4 but the 2 wires blue & brown I don't know where they go
Brown & Blue are typically the colours for mains wiring Live & Neutral respectively. Black & White the US equivalents. Black & White will be the supply into the equipment and Brown Blue the supply into the switch.
It will not (should not) make much difference where you attach Brown & Blue - worst case you might blow a fuse - just wire them up best you can on the other end of the switch to the two wires you've already attached.
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