Faulty fuel guage 1997 blazer reads past full

Did you check the fuel pump?
If you did, check for a grounded wire somewere by the pump.

USSUALLY WHEN GAGE GOES WAY OVERFULL IT'S A BAD GROUND
QUICK CHECK USE BOOSTER CABLE ONE END ON TANK OTHER END ON BATTERY NEGATIVE IF GAGE GOES OK MAKE UP SHORT WIRE FROM FRAME TO TANK SEEM LIP
AND ATTACH MAKE SURE METAL IS CLEAN

fueltank sending unit inside fuel tank is broken or the wire is disconnect.when guage reads past full that means the guage is not getting a signal from fuel tank

Hi, The 1999 blazer has a fuel level sensor mounted in the fuel tank. It is mounted to the module that contains the electric fuel pump. The tank must be removed in order to service this module assy. When the level sensor is faulty, it can cause the guage to read erratic, or incorrect. If the computer senses a fault with the sensor, the check engine light can come on, and the fuel guage can drop to empty. A code can set for the fuel level, and this sensor can be replaced seperate. Good luck... Coop

I would guess that your sending unit from the tank is grounding out which means it need to be replaced in most cases. If the gauge is bad, it will usually effect the other readings in the cluster.

Test the gauge by using a test light ,and grounding the test light clip to a good known ground,then touch the pink wire on the connector harness going to the tank,with the connector unplugged,and key on,the gauge will move slowly to the empty mark,and lower ,then remove the test light and it will go past full,if it does this,it is a good gauge,and the sending unit,was put in wrong,or the part was bad.

should be a grey wire going to the top of fuel tank connects to fuel guage / when the guage in the tank reads grounded it shows full , no ground it shows empty. if you ground that grey wire and the guage jumps to full then faulty guage if nothing maybe bad ground on the tank itself. the guages are a reostat like a tyco race car gun the more it moves the more it grounds .. good luck

Most likely the fuel level sending unit is defective. I have also seen a faulty voltage regulator cause a fuel guage to peg out. (Go past full and not move). I don't know if it is the problem in this case, but it is something to consider. Hope this helped and best wishes.

If sender is new in the fuel tank, you have a wire problem between conection of fuel sender and dashboard gauge most likely place at dasbboard gauge.

You are going top have to pull the gas tank and change the gas guage sending unit, it is the cause of your erratic guage readings, of this I am 100% sure.