Does the brake warning test need to be operable at all times?

I am not using the third point on the ignition normally used for turning the car over but this would mean it could only be used when the engine is not running.

Normally it'd be from an ignition or accesory feed (IE. pos' 1 or 2 on the key).

I assume you mean you're useing a start button and therefore the start pos' on the key could be used for fluid test? It'd be down to the testers judgement, so I wouldn't. It'll cut the engine any time you test it. Just put it through the handbrake warning light.

As above, use the handbrake lamp and make it live with the ignition on

Might be a pain to wire. Fluid level test usualy wired supply, bulb, switch and earth.

Ok, thanks. I cant use the handbrake warning light 'cos i dont have one and dont have room to mount one.

Is there any reason why it cant be wired to headlight flash, horn or the unused button on the indicator stalk for the trip computer.

I know the IVA manual says that buttons should be correctly labled though.