i have a 2003 ford mustang gt and both remotes just stop working put new batteries and all that can some one help?

If new batteries don't do it, reset system by disconnecting battery for a minute and see if it resets itself

after you put the new batteries in you will need to re-program both of your remotes, No need to pay the dealership to do it - just follow the steps below. Please note: the instructions must be followed exactly! Remote Transmitter Programming NOTE: All remote transmitters must be programmed at the same time. The vehicle must be electronically unlocked before entering program mode (via remote transmitter, keyless entry keypad (if equipped) or door lock control switch while the driver door is open. Turn the key from OFF to RUN 8 times within 10 seconds, with the eighth turn ending in RUN. If the module has successfully entered program mode, it will lock and then unlock all doors. Within 20 seconds, press any button on a remote transmitter, and the doors will lock and then unlock to confirm that each remote transmitter has been programmed. Repeat this step for each remote transmitter. If the door locks do not respond for any remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Inspection and Verification. Make sure that no more than the maximum number of remote transmitters are attempted to be programmed. Exiting the programming mode is accomplished if one of the following occurs: The key transitions to the OFF position. 20 seconds have passed since entering programming mode or since the last remote transmitter was programmed. The maximum number of remote transmitters have been programmed.