Gas Gauge not working, Check Gauges light on

[strowhat]

Hello, Just changed the fuel sending (level Sensor) unit on a 2000 Sunfire with a new part for ORielly Auto Parts. No change from the prior issue, I never know the correct level in the tank.

The Symptom is when I start car, gas gauge goes to full and then after some time (seconds to a Min) it drops to empty regardless of the actual level. Same with half tank, full tank, or even empty. Also on dash Check Gauges Light comes on when level drops off. This prevents low fuel level on dash to work.

Where would my troubleshooting continue? Grounds for PCM?
This is a second hand dash Cluster, could this be the issue?
What Pin (s) would I check on the PCM for fuel level being sent?
I read somewhere 5 volts?

Any help appreciated!

Thanks Chuck (Strowhat)

 

[melsg5]

Why did you replace the cluster to start with? Did the gas gauge issue start after the cluster change?

 

[strowhat]

Changed it out do to half the dash not lighting up, got the car used and another possible issue connected the radio harness has been cut and aftermarket radio was in it. Now I tried a second cluster and still the same not fuel gauge all the rest works fine. PCM was not mounted in wheel well so I bought the mount and remounted. No idea if this could be a problem related.