Can anyone offer advice on troubleshooting my keyless entry transmitter on my 99 C-5? I have reprogramed in accordance with the owners manual and it will only work for about a minute. the battery has been replaced.

Best thing to do first is to have it scanned for trouble codes and look for any body control codes. You might have something that is messing with the BCM (Body Control Module). Eliminate that 1st. [8D]