Ok, interesting issue here, hoping someone has had this before. 2008 Suburban 2500, 6.0 LY6, 192k miles, stock except for Blackbear tune.

I don't drive this truck frequently, and when I do I always use remote start. Well, this morning, after driving a bit and stopping for a quick errand, I jumped in and tried to start using the key. Just got a click, as if the battery was dead. I took out the ignition key, open and close the driver door, then try to remote start and it fires right up. Shut it off, try to start with they key - just the click and no start. I can insert the ignition key and turn it to run after remote starting and the engine stays on. I have no idea how long this situation might have existed.

Any thoughts? I'm going to start digging around and checking wiring, but this one has me perplexed. TIA

 

I would suspect the transponder in the key, maybe signal is enough to keep it running after remote start but not enough to sense it for starting? vise versa, maybe the transponder reader? Do you have a spare key to try?

 

Both keys behave the same. One of the first things I checked.

I'm guessing my primary battery was low enough on voltage to not have enough juice for a keyed start, but enough juice to start remotely with fewer current draw. Or perhaps the second battery is tapped differently on keyed vs remote start.

I have a charger on the primary, will check it when I get home tonight. Have to figure out if the infrequent usage just caused it to slowly drain (and my short trips aren't enough to fully charge it) , or if the battery is dying or has a bad cell or two. It's garaged, so it isn't exposed to extreme heat or cold.

 

Update - problem solved. A PPV owner suggested the primary battery might be dead. Saved me a bunch of troubleshooting and the hassle of replacing an ignition switch. Pulled out the primary, moved the secondary to the primary position, connected the cables, and she fired right up with the key.

Good to know this behavior for the future. I always wondered about the interaction of the two batteries if the primary was dead. Now I know.