Where to run a wire from Engine Bay into Cabin

[SilverBeast]

I want to run a wire (or two!) from the booster heater temperature sensor (clipped to the wiper mechanism) into the cabin.  Can anyone suggest the best route to take to get the wire through the bulkhead into the cabin?

I'm doing this to be able to fit a switch that will allow me to overide the low temperature requirement to allow the booster heater to come on so I can:-
(a) Check it is working OK since I stripped it down and rebuilt it.  Though I didn't find anything obvious so suspect it isn't!)
(b) Allow the cabin to warm up quicker as it is so cold at the moment ! 

[Chrispb]

Hi
If you look down the bulkhead behind the gearbox area there is a large rubber grommet.
Inside the car It's to the left of the heater blower.

[SilverBeast]

Thanks

[Mirez]

That's where I would have suggested as well - Quick tip: pass your wires from the cabin into the engine bay - it's a bugger the other way around!

[SilverBeast]

Good point, it's the little details that make the difference!