Fuel Probes
If you have already changed the fuel probe(s), and are still getting a faulty indication ( like "LOW FUEL" ) and you know your fuel tanks are well above the low fuel level then I suggest you check the CISO card on the faulty side, sometimes the CISO cards can latch on a defect (such as LOW FUEL)and will not release it, thus every time the battery switch is turned on the CAS Message "LOW FUEL" is on. Swap out the card with the one in the opposite MAU if the snag transfers to the other then you know its the CISO card at fault. Note the CISO cards can also latch on to other defects also and display them as a CAS message, its something to do with the logic circut in the CISO Cards.