The battery in my keyless entry fobs don't last more than two weeks. I'll put a new battery in and within two weeks it is DEAD 2.25V. I use the recommended #2032 battery type. At first I thought it was a problem with the #1 fob. So I started using the #2 fob but that did the same thing. They work fine at first then range gradually decreases over time then go DEAD.

Welcome to the forums James.

Are we talking about the Key FOB'* for your 2007 GMC Sierra Classic?

I cannot think of anything that could drain the batteries that quickly, not given what you have stated.
I did read that some people claim having a cell phone too close to the key FOB'* can cause battery drain, maybe somehow it is trying to communicate with the transponder, not sure how though.
Also read strong magnetic devices may be responsible, but I am not sure how this could happen.

Do you keep the FOB'* near a cell phone a lot, or near any battery chargers?

It is both FOB'* for my 2007 GMC. This started within the past month or so. I've always kept my phone (same phone for years) in one front pocket and the FOB in the other. Sounds like it is an issue with the transponder in the vehicle since it affects both FOB'*. How would I troubleshoot it?

I understand that it is with both FOB'*, was just posting the only info I could find on the issue that could possible effect both FOB'*, the transponder could somehow be causing this, and to me it is the only thing that makes sense, I am sure somebody more familiar with the transponders will post and provide some help soon.

it must be common to both, like you keep it in your pocket and the button gets pressed or you got the batteries at the same place time and they are old or something. the thing is not a receiver that i know of should only do anything when you press a button

That is what I thought, but I did read where one guy said he kept his on a belt clip, and was sure that he never accidentally pressed the buttons, it does make sense that the buttons would need to be pressed for the circuit to complete, and draw juice from the battery.

Have you tried the Energizer brand batteries, I have heard they are the better batteries to go with.

I don't understand how anything else could be doing this besides a button being inadvertently pressed. Typical key fobs are one way transmitters. In its current state, the key fob is not using any energy until one of the buttons is pressed.

This started in late March with #1 FOB. The battery lasts 2 weeks each time. The past two times I got the #2 FOB off the shelf, put in a new energizer and it lasted two weeks. I replaced it two weeks ago on 5/6 and now its dead. I don't know how the transponder works but it makes sense that it is one way making both FOBs the problem. But I haven't changed my routine in years. The FOBs are stored and handled the same way now as I did 6 years ago when I got the truck. I'd hate spending $30 for a replacement FOB to find that it didn't fix the problem.

Could it be that the rubber buttons are misaligned when reassembled causing the battery short / drain?

Got any rubbing alcohol and Q-tips?

Disassemble the FOB'*.
Remove the battery.
Dip the Q-Tip into the RA
Clean the boards front and back
Clean the backside of the rubber pushbuttons.
Dry
Reassemble.
Come back in 3 weeks.