When my gas light comes on during the day my horn blows every couple minutes at night time the headlights go from highbeam to lowbeam every couple minutes. Also my check engine light is on more than it is off
@Chippy78…have you taken the Dakota down to your local auto parts store and had the codes read on the computer? While you’re there…have them check the voltage on your battery and test your alternator. Post the results of the CEL codes and we may be able to help you. Right now…we would probably just be shooting in the dark trying to come up with a fix.
Sorry I had to say it, keep the tank full. 
You have more problems than the low fuel light.
@missleman is correct. Dodges seem to be sensitive to low voltage. Also, make sure your battery connections are clean and not covered in corrosion. Clean and check all motor and chassis grounds.