After installing the repaired LCM, alarm goes off any time the key fob is used. Does the key fob need to be reprogrammed?

The problem is almost never the LCM. The light control module isn't responsible for the alarm going off. Tracing down the exact issue can be tricky due to there being so many switches and sensors.

Faulty hood or trunk switch, and door jam sensors can be the issue. Using an OBDII tool, see if there are any codes in the body control module regarding anti-theft. Also, check to see if any diagnostic lights or warning messages turning on when the alarm is going off.

 

If nothing seems to resolve the issue, a hard battery reset is recommended to reset all computer modules safely back to their original state.