Karcher 620m no power (95% of time)?

Hi,

My Karcher 620m has no power 95% of time. The green light is NOT lit and the motor does not turn on. However, 5% of the time, it will turn on and work without issue, both green light on and motor fires up. Strange!

I have stripped the casing off and confirmed the switch is latching when pressed as I first suspected the external button wasn't engaging with the encased switch. I suspect the internal switch (part 8) could be the issue, but cannot understand why it sometimes works, surely the switch would work or not? Karcher said they haven't seen this before and want £103 to fix with only a 3mth warranty on replaced items or they said "have you seen the new models we sell on our website". I don't want to buy a replacement switch on a hunch, so if anyone is able to help, I would really appreciate it.

Thank you in advance,

Stuart