Before changing the batteries in the RKE transmitter, make sure nothing is touching the metal near the batteries and do not touch the new ones until they are clean; to clean them, use rubbing alcohol if they come in contact with oil from your hands. Slide a small coin under the center seam between the case halves by the key ring, at the tiny indent in the center to release the two pieces, being careful not to flatten the rubber area. After that, open up the side of the transmitter where the buttons are and remove both batteries. Use new 3V Lithium 2016 cell batteries, making sure that the marked plus sign is pointing upwards inside the transmitter case. The final step is to place the case halves in position, squeeze down on them firmly and evenly and listen for them to snap together before testing the transmitter's performance.