Keyless Entry Transmitter Replacement

[starcrwzr]

I'm new here, just having bought a 2001 Ram 1500 with 81K miles on it. The previous owner gave me a keyless entry transmitter that he said didn't work anymore. I opened it up to check the battery and found the battery contacts a little corroded, so I cleaned them off and checked the battery and it seemed OK. So I tried it on the truck and the unlock button unlocks the doors, the same button locks them when pressed a second time. The lock button doesn't seem to do anything. Anyway, is there a replacement available for this fob, since the plastic that the keychain would go through is broken? And is this normal operation for only one button to work? Anyone else have one of these. The previous owner said that is was installed by the dealer and activated an alarm, but I have no way of knowing if that's true. Here's a picture of the fob...

 

[Calab]

Sit in the truck. Lock the doors with the fob. Open the door - you should hear your alarm.

Hopefully the alarm turns off if you unlock with the FOB or put the key in the ignition.

 

[starcrwzr]

Thanks Calab, but nothing happens when I open the door after pressing the lock button inside the cab. I've tried the other procedures in the manual and still only get the lock and unlock function. I fear that this some sort of dealer add-on that only unlocks the doors and is not the equipment from the factory. Or, the fob is malfunctioning and is only transmitting the unlock function. I guess I'll try buying a replacement on Amazon and see if I can program it to work correctly.