Would it be possible for bad grounds to prevent the truck from starting when it's "cold"? It starts right up when it's warmer, like mid morning.

 

I would say yes. Might not be my first choice of things to check (kind of hard to tell - won't crank? Crank but won't fire? etc. - more info would be better) but could be. If cranking but not firing, I would suspect an electronic issue more - a circuit opening when cold but closing when warm, for instance. If it refuses to crank over when cold but does when hot I would check things like sticking brushes in the starter, bad ignition switch, solenoid not working when cold. For what it's worth, that 'dust-off' cleaning product does a pretty slick job of cooling things down - if you think something like an ignition module is bad when cold, but seems to work fine when it's hot: thoroughly spray it down with the dust-off and it suddenly stops working, that would be one diagnostic and you can do it without having to wait for everything to cool.

 

You bring up a very good topic, Vanya, one too many of us (incl. me!) forget and neglect. Cars have LOTS of grounding points, and they all can loosen or corrode or whatever. It certainly shouldn't be so amazing that fixing all the grounds suddenly makes things work a lot better, but for example when you see how much brighter the faded taillights and brake lights on an old car work after you clean up the connections and replace the old bulbs, it really is rather striking.