Truck in question: 2001 Silverado 1500 LT Z71 (w/ Stock Keyless Entry System)
Okay, I really didn't want to make a forum post, but I've scoured the hivemind for answers and I have found none.
Recently I ordered new batteries for my 15732803 key fob that was showing signs of a weak battery. i.e. Required holding button longer than before, and requiring me to stand closer.
I removed the old battery about 12 hours before installing a new one. (idk why I did this, but I didn't think it would cause issues.) I tested the fob at Pep-Boys on one of those Energizer fob testers. Seems to work fine!
After installing the battery, I followed the instructions on the inside of the fob case. "Press and hold LOCK & UNLOCK for 7 seconds". I did this, but I received no response from the truck. I tried this several times to no avail. At this point I assume that removing the battery for an extended period caused the rolling codes to become lost or out of sync... I begin attempting to enter programming mode as per my trucks service manual.
This is where I am having problems. I followed the service manual and a multitude of other online resources that gave me the same, or slightly differing instructions. However, the locks NEVER cycle when I release the drivers-side UNLOCK button. I tried different combinations of this, with different speeds; removing the key, opening and closing the door every time. No luck...
The systems worked well for years until I removed and replaced the battery.
I respectfully ask that you don't respond with programming instruction from the service manual. I've read it so many times I could recite it by memory. I am certain that it's either a hardware/software issue, or it's a process issue. Maybe I'm performing the procedure too fast? Too slow? Are there known quirks that are undocumented in the service manual? Did I somehow mess something up by leaving the fob battery out for so long? (This seems unlikely since the fob isn't the issue in question)
Thank you in advance for anyone who responds.
I know this is a pretty old thread, but I finally fixed my keyless entry system! Behind the instrument cluster, in the top right corner there is a small black box. This is the keyless entry module. Turns out is was just not plugged in. Just before I originally made this thread I had a mechanic replace my heater core which requires complete removal of the dash. When putting it back together they must have just forgotten to plug it in, or it wasn't secured and came loose. Either way, I just plugged it back in and the truck enters programming mode just fine. Bought a new fob and everything works perfectly. I hope this thread can help some other poor soul who just didn't think to check the connection.