formariz 12,051 #1 Posted August 17, 2021 My 520 started reading full all the time now. When shutting it off it moves to empty but when power is applied it stays pegged at full. Float issue probably stuck or sending unit gone bad. Any thoughts? Share this post Link to post Share on other sites
lynnmor 7,903 #2 Posted August 17, 2021 5 minutes ago, formariz said: My 520 started reading full all the time now. When shutting it off it moves to empty but when power is applied it stays pegged at full. Float issue probably stuck or sending unit gone bad. Any thoughts? The wire may be pinched and shorted. If you do need a sending unit, read my post here. 1 Share this post Link to post Share on other sites
Handy Don 14,239 #3 Posted August 17, 2021 Definitely Share this post Link to post Share on other sites
squonk 44,036 #4 Posted August 17, 2021 I would also look to an open ground in the sender circuit. Back in the day, my brother's Chevy II would lose the tank ground and the gauge would read full all the time. 1 Share this post Link to post Share on other sites
roadapples 6,984 #5 Posted August 17, 2021 13 minutes ago, squonk said: I would also look to an open ground in the sender circuit. Back in the day, my brother's Chevy II would lose the tank ground and the gauge would read full all the time. I've got that problem now with my truck.. Share this post Link to post Share on other sites
lynnmor 7,903 #6 Posted August 21, 2021 This may help diagnose the problem: 1 Share this post Link to post Share on other sites
