[:@] I am haveing a problem with my 1990 vette fuel gauge. It readsempty all the time even when the tank is full, I followed the diagnostic flow chart in my GM service manual and when complete it said to replace the central control module. I did this but the same problem remains. Does any one know of, or has had this problem and solved it? The service manual doesn't go beyond diagnosing the CCM and Fuel level sensor. How does one diagnose the speedo, fuel gauge, display LED module to see if that is the problem?

 

If it reads empty, you have a grounded circuit on the sender wire somewhere. Maybe sending unit, could be gauge cluster. Open circuit will read full, grounded will show empty.

 

it could be the sender in the tank.


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Fuel sending unit?

 

on a 1990 coupe to check the continuity of the fuel sending unit wire which should be a ppl colored wire going to the control unit where are the connectors to take apart to verify continuity from the sending unit my fuel gauge stays at 3/4 full to full