Check your battery, it can be weak or dead. If the battery seems fine, your alternator may be weak or needs replaced.
headlights
Fuse for parking lights probably blown.
What year is the vehicle? Did you check the fuse?
Dodge Rams are not equipped with Daytime running lights.. Although what you can do is turn on the parking lights and select just your fog lights (if equipped) otherwise to have running lights you will need to turn on your headlights. It's not a huge advantage to have running lights, because when the climates come that you need to turn on the headlights anyways, they aren't necessary.
Well, the daytime running lights are on whenever the car is running and in gear. They're off when you have the headlights on. So, your service light Doesn't come on when the headlights are on?? If you switch the headlights between on and off (with the car running and in gear) does the service light follow?
Try applying parking brake
how do i fix my daytime running lights on my 2001 grand prix gt headlights work perfect
Those aren't headlights, they're considered running lights or parking lights. I believe that mercury calls this a Light Bar.
You may have a pull on your batt, or a surge.
If the lights flicker when the vehicle is running, the alternator is on it's way out.
Often this type of behavior is caused by a bad ground for the lighting circuit. Check the ground circuit for the brake lights.
I take it you have daytime running lights , if so by engaging the emergency / parking brake the daytime running lights should go off