First it stopped working. Then a day or two later it started jumping to different levels at start up. Now it's flipped all the way over and interfering with the temperature gauge. Could this be the gauge, sending unit or relay? How do I test the system to see which one is bad? Where is the relay for the fuel gauge?

 

the gauge stepper motor is faulty. I've replaced the tach, speedo and temp steppers motors on my 05. If you can solder, you can buy replacements from ebay and solder them in. the kit I bought came with instructions. do an ebay and you-tube search.

other option is to send the cluster out to a cluster repair business and they can replace one or all of the stepper motors.

 

My problem is just with the gas gauge. Is this a realistic solution?

 

have a shop do a gauge sweep with the scan tool. this will determine if the fault is either the cluster or the fuel sending unit or wiring.

 

If you do the work to replace one stepper then you should replace all of them. They aren't that expensive and you will save yourself the work of removing and taking the cluster apart at a later time.

 

with old chevy. you can buy kits pretty cheap and im not even sure you can buy just one. my 04 imp had 4 out of the 6 gauges acting up. im not even sure if you can say that i can solder good but i replaced all 6 with no issues. i did also use a desoldering tool and i do suggest one to help out