Mercury Mariner key fob battery
3 of the 7 model years listed for the Mercury Mariner have a proven battery. The most common answer is CR2032. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.
- 2005-2007Remote (separate)
CR2032
FCC ID CWTWB1U331 / CWTWB1U345 / CWTWB1U311Two sites agree: uhs-hardware.com and americankeysupply.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2008-2011Remote (separate)
Not confirmed yet
Changing the battery
Separate remote fob
- This remote is its own fob, separate from the metal key, which makes it one of the easier ones to open.
- Look for a screw on the back or a notch on the edge. Remove the screw if present, then twist a coin in the notch to split the case.
- Replace the cell, keeping the + side where it was, and check the small metal tab still touches it.
- Reassemble and test from a short distance.
A CR2032 is 20 mm across and 3.2 mm thick. CR2032, CR2025 and CR2016 share the same width but not the same thickness, so a swap between them can leave a loose contact or a case that will not close.
Coin cells are a choking and burn hazard for children. Store the spares in their original pack, out of reach.