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Q: Gas gauge not working

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Had alternator replaced for the third time in 4 /mos turns out was a loose wire ($900 later) gas gayge & heater gauge not working now!!! Im so sick of this im thinking of getting a diff vehicle....whats wrong now??? Mechanic said they werent working this morning either...not his problem i guess...what could it possibly be???
My car has an automatic transmission.

The gas "level" gauge relies on a sending unit in the fuel tank. You’ll want to first confirm that the fuse in the circuit is in place and has continuity. If there is no issue there, the sending unit is then tested (per Factory Service Manual specifications) and the circuit from the sending unit to the dash gauge is confirmed to be intact (i.e., no shorts or opens and working ground).

Finally, the dash gauge is tested. Usually the sending unit in the tank fails and/or the wiring in the circuit has a break. By heater gauge, I presume you are referring to the engine coolant temperature gauge.

A similar protocol is following, that is both component (in this case a sensor screwed into a coolant passageway on the engine head) and the wiring are tested until the fault is found. If the mechanic replaced the alternator, instead of correctly diagnosing a "loose" wire, it is unlikely he or she will be able to diagnose your new issues without comparable, or worse, problems. If you want to get a second opinion on the faulty gauge readings you are experiencing, YourMechanic does offer a diagnostic for non-working electrical components, such as for the dashboard gauges.

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