I have a 2003 Silverado and the oil pressure gage is maxed out as soon as the key is turned on without the motor running. It stays maxed out when the motor is running. I know I don't have an oil pressure problem. I replaced the stepper motor in the gage cluster and that didn't help. Before I tackle the sending unit I'd like to know if that's the only probable cause for the gage failure. Thank you

 

check the wires to the sending unit... maybe a short somewhere