Turn the Ram's ignition to the "on" position but don't crank the engine.
Pull down on the fuse cover panel in the Ram's driver-side foot well to remove it.
Locate the fuse for the electronic control unit (ECU) and pull the fuse using the fuse pullers in the fuse panel.
Wait three minutes and put the fuse back. The Check Engine light should be off.The Check Engine light in a 1998 Dodge Ram comes on when the Ram's electronic control unit (a mini computer that monitors engine performance) generates and stores a trouble code or codes. These trouble codes refer to various sensors on the Ram. Normally, these sensors have a very long service life in excess of 75,000 miles. However, they do eventually fail. When they do, you'll want to replace them to keep your 1998 Ram running at its best. Once you've fixed your truck, you need to know how to reset the check engine light.