How to Replace the Key Fob Battery in a GMC TopKick

1. Separate the transmitter by inserting a flat, thin object into the slot near the key ring hole.
2. Remove the old battery.
3. Insert the new battery with the positive (+) side down, using a CR2032 or equivalent.
4. Align the transmitter halves and put them back together.
5. Test the transmitter to check that it works.

• Do not touch any circuitry on the transmitter, since static from your body could damage it.
• If it does not work after the battery change, it may need resynchronizing: stand close and hold LOCK and UNLOCK together for at least five seconds.

Source: 2010 GMC TopKick owner's manual, PDF pages 70, 71. Steps are summarized in our own words (AI-assisted, checked against the cited pages 2026-10-18). Other model years can differ; your manual has the final word.