While driving the gas gauge on my 99 Tahoe suddenly spun around to 180 degrees off. Now instead of pointing up it points down. Full should be posting up and right now it is down and left. Empty should be up and left and is now down and right. Anybody know why and how to fix it?

 

In my experiences, 9 times out of 10 its a bad fuel level sensor, not the gauge. If I am correct, you will need to pull the gas tank to replace it.

 

post a pic on the gauge so i can see which build you have. if its a 99 new body style; its probably a bad cluster stepper motor. the clusters were so bad in this gen they extended the warranty coverage on the clusters to 10 years.
when the level sending unit or wiring go bad; the gauge reads wrong but still withing the range of empty to full.

 

Gauges with key off
Fuel gauge with ignition on. Based on mileage driven since the tank was filled it should be almost empty

 

looks like a 99 old body style cluster. not sure if it uses stepper motors...if it does...thats where i would start...much easier fix than sending unit.
youtube cluster stepper motor repair or gm instrument cluster repair.

 

Thanks for the input. I wasn't looking forward to dropping the tank. I did that a few years ago to change the fuel pump.

 

According to the dealership it does not have stepper motors. Any body know where I can get a custom gauge cluster since I have to replace it?

 

my dads did that, but there was a little pin to stop the needle,
& the needle just slide on top of the pin
my dad just took a wire & bent the needle a bit