My 'check gages' light came on?

I've had this car for 8 years now and everytime this light has come on it has been related to low fuel level. yesterday it came on when I was at 1/4 tank. I thought it was odd that it came on so early and though maybe the fuel sending unit was failing. this morning I filled the tank and the light stayed on. I only have four gages: fuel, temp, speedo, and tach and all of them are functioning properly. I did replace the water pump and brake pads and rotors two weeks ago.

Also, I dont know if its related but the door locks on the remote entry stopped working right around the same time. the alarm arms itself and the trunk opens fine but the door locks no longer actuate.