This needs really no thought - I will mention it again as it seems everyone chose to gloss over my comment.
Buy this: PRC7925 its the proper part for the job made by LR for the expansion tank fitted!
All you need is some wire, an ignition live, and a warning lamp somewhere.
well i went and got this but theres a problem,under normal use there is continuity through the switch,problem with this is the warning light would be on all the time,how do i get round this?
i mentioned that above with a possible fix
ah right sorry missed it
let me know if you find a low signal nc switch that works.. or a different solution
thinking of using this,someone on Series and fenders on fb,gave a simple way to wire it using a relay Premium Quality Automotive Relay 12V 30/40Amp 5Pin C/O With Bracket - By TYCO/TE | eBay
Earth to one side of float, other side of float to 86
Fused batt (adequate for bulb) from ignition on feed to 85 & 30
87a to bulb
Earth to other side of bulb.
If I make some controllers - anyone interested?
personally, i'm not as they are meant to fail quite often anyway.
but i'd be interested in links to parts to make our own. i'm not ace with electronics.
you taken the internal 680ohm resistor into account?
If I make some controllers - anyone interested?
is this theory or have they bought and done it?
it looks like that float has a resistor in it which might not trigger a normal relay.
Cheeky bugger. What fails often?
Of course i have taken this into account. It wouldn't work otherwise