Possible CTIS and coolant leak. please help!

[3Hummer]

Alright guys

First CTIS:
So I think my truck has a leak in the CTIS system. I recently came back to my truck from a few day trip and the tire pressure was down to about 10 PSI in the front tires only! The back were fine. I re-inflated the tires. drove home. Parked it overnight, lost only a few PSI (it was cold so that could be it) and then drove it back to the airport and now I'm out of town again for a few days. If its low again when I get back I have reason to believe its a leak in the CTIS system as both front tires were low the first time I don't think its a nail or something else causing a flat. Any advice on what this may be or what to look for? I'm not technically savvy so if it happens again I'm just going to have to take it in for service unless someone can give me some advice on what to look for.

Second the coolant.
I walked outside one afternoon and saw some coolant on the ground below my truck (some green fluid) I turned the car around, opened the hood and couldn't find where exactly it was dripping from and the coolant level seemed to be in the normal place just barely below the fill line. I did not notice any more coolant on the ground that day or the next morning. Again drove the truck to the airport and out of town for a few days. Came back to the truck notice no spots on the ground, opened the hood checked the coolant level it was still in the same place. Drove it the entire next day without noticing anything and then That night on the ground i noticed a very minimal amount again (maybe about two quarters size). Again moved the truck and again the next day checked the coolant level and it was fine. Next morning noticed nothing on the ground before i left for the airport and checked the level and it was still in the same place. So now I'm out of town again as I've said above so ill check it again when i get back to the truck. But what should i be looking for exactly? Is it normal with some serious temperature changes for something like this to happen (its at my place in Charlotte, NC and recently the temperatures have been fairly warm one day, then drop to freezing for a day then back up and so on) If I see more or no advice on it I'll have to take it in for this as well.

Thanks your help is greatly appreciated!