Well, my budget got a stay of execution. Maybe.
NoCo battery tender for 24 hours, starts right up. Have to tow a friend's dead Dakota an hour after work today so I had the truck out getting the dolly out, organized, tires inflated, test tow...got back, parked the truck. Checked under the tonneau to make sure I had space for a spare, a jack, and some tools for the tow - my work lights were on under the cover.
Most of the truck's use is my sound company. I do shows that end well after dark, so under the flip-up tonneau cover I have an LED light strip so I can see what I'm loading. It hasn't worked the last couple gigs (I need to troubleshoot the wiring)...but apparently I left the switch on last time, because those lights were on when I opened the tailgate yesterday.
DOH.
Turned them off, put the truck back on the NoCo overnight...fired right up for work today.
As an aside - the FlowKooler water pump I just installed is definitely working. Used to be I'd hit 190 on the way to work, easy, and the thermostat would do the regulating. Today? Barely cracked 150, and that's with the cold front 3/4 closed.