Some parts stores have a little test receiver at the counter to check it.  It
also has a "coin" type battery in it similar to or identical to most computers
that must be replaced occasionally.  They test it and sell you a new one if
required.  If it is dead, you can get another key fob off eBay and program it
for your vehicle with the instructions provided.  They are much cheaper on eBay
than at any dealer.  I would test for a dead battery first.

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