Car fuel sender units provide the absolutely essential function of working the fuel gauge. Obviously, if the car fuel sender ceases to function correctly there exists a very real risk of running out of fuel, which may leave the driver stranded in a difficult situation. Hence, it is essential to ensure that the car fuel sender unit is functioning at all times. If the part requires replacing it is not overly expensive or difficult to change, something even a casual DIY mechanic should manage without a problem.
There are symptoms that indicate if car fuel sender units are not functioning correctly, the most obvious being a fuel gauge that is sitting at empty when the car is full of fuel. A more subtle indication, however, is a fuel gauge that tends to jump up and down erratically, showing a full tank one moment and a half tank the next. If you are noticing these symptoms the problem may very well be the car fuel sender unit. Also keep in mind the possibility of a leaking fuel tank, which is a dangerous problem and can be identified by a smell of leaking petroleum.
If you are certain your car fuel sender unit is the culprit and requires attention, make sure it cannot be repaired before buying a new part. Many online guides exist on how to repair the part, so simply look around and a solution will be found. If, however, the part cannot be repaired or you would prefer to replace it, be sure to get the correct car fuel sender unit for your particular vehicle. You may also request the advice or services of a professional mechanic if you are uncertain about any of the details.