Gauge ohm range

Testing the under dash harness alone. every sender should show something. Fuel sender will show between 80 and 10 ohms depending on how much fuel is onboard.
Oil and Temp senders with engine off and cold. 80 to 90 ohms.
Best to test at senders terminal to senders outer body first, then test for nearly same readings under dash.
Gray wire is oil , purple wire is temp, dark blue no tracer is fuel.