G'day iv got a au falcon ute on LPG and the fuel gauge doesn't work it is always showing empty and when it does it says it full does anyone know what the problem could be?

And iv also had a few problem when iv had my drivers door open when I go to open the passanger side door with the middle door open button the car lockes keep popping locked and unlocked and stop with the doors shut and the key won't let me open it for about half an hour or so any help will be greatful

Hope some of this may help solve your problem.

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Sender has two screws securing it to the tank, easily obtained and replaced. But first I would be looking at the wiring connections and in particular the earthing of that sender.
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It could be a faulty gauge on the tank I would say. If you decide to change it yourself ( illegal) make sure you use gas tape and not water tape. Also check the wires from the gauge as well as they might have some corrosion on them.
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I had issues with my LPG senders ... so i had them replaced (ute runs 2 tanks for EGAS).

Also ... in a ute ... there's a bog connector on top of the support where it runs across between the 2 tanks ... this gets dirty and gets a dodgy connection (some days it would read OK ... others it would ready nothing ... and other days it would say full).

I disconnected it (to get to) by reaching up over the tailshaft then above the LPG tanks and disconnected it ... and cleaned it with electrical contact cleaner ... and clipped it back together.
Was all good after that .... mainly happens on the ute as there's so much crap under there.
Helps if you use a hoist ... expect to get filthy doing this ... arms also get sore from trying to get to the plug. If it's tray back it is easier to get to ... Styleside is a totally different kettle of fish though.
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Open the Flap on the tank and on the gauge there will be 2 connections, one will go to the tank body, note the colour of the other one, that one should go to the Signal connector on the change over Switch / Gauge. The 12v and Neg should be obvious. The gas connection should go to the soleniods to open up the gas valves. Petrol one is likely not connected but may be wired to a relay to cut injector power.
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I would say sender on LPG tank. I had same problem on EL it used to stick sometimes. PM GASMAN he sometimes has some senders. Not that expensive either i think $30 -$40 for a new good one or $20 for a cheapie. 5 minute job to install too. I know how annoying it was working from distance travelled. It used to * me right off.
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