BMW key battery?

[ZJohnson]

A friend has a '88 BMW 528e with a mild problem. The key itself has a small button that when pushed unlocks/locks the doors. This remote function has stopped working. First guess is that the key has a small battery that needs replacing. The nearest dealer is ~ 100 mile away. ? internet sources? Second possibility is that the key is "charged" by the ignition and has a built in replaceable battery that either has died or the "charging" function has stopped. ? suggestions?

 

[Tosh]

Go with your first guess. Then have your friend order an owner's manual online.

 

[NYEngineer]

There's a battery in there most likely a watch type battery. My buddy has a store that sells nothing but batteries. It's called the Battery Terminal. He has a toll free number. 1 800 356 6624.