How do you reset check engine light on 2003 dodge ram?

There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.

By repairing whatever tripped the light. Then you use an OBD2 scan tool to reset the light. You just have to disconnect the battery for a minute and then the check engine light go off, if the problem has been fixed!!! Disconnecting the battery will reset the light on most, but not all, 1995 & older cars, but on 1996 and newer cars this will rarely reset the light. It requires an OBD2 scan tool to reset the light on most newer cars.

There are pages and pages of things that can cause a check engine light. You need to have it checked with a scantool. Then the code can be diagnosed and repaired.