2000 Silverado Low Coolant Light comes on

My low coolant light comes on - this started after I had a run in with a deer
about six months ago - someone told me that my computer took a jar and to disconnect battery to see if this reset it. I'v added coolant several times
and the light is on again. I noticed a couple of days ago heater is blowing out cold air. Any suggestions ?

I just went thru this with my 03 2500hd and my wifes 03 1500 z71. hers was very slow and the message came on. I looked and looked and couldnt see any leaks. I could smell it when it was wrm finally had to get the trouble light remove the splash shield and skid plate and really look. it was a small leak around the water pump gasket on the passenger side. it would drip down and evaperate on the warm engine. the gaskets only cost about $20 and I also flushed the coolant since it was drained anyways. about 2 weeks after I did hers I smelled the same thing on mine but it was the drivers side and smaller. so did the same thing. they both use the same pump and it took only about an hour and a half. my truck has 110,000 and hers has 70,000 and the dexcool in both looked fine, not dirty gelled or anything else. good luck.

also check the plastic side tanks on the radiator as they will get cracks in them. also the impact could have crack the one on the impact side. you can replace the plastic tanks instead of replacing the whole radiator. the tanks cost$ 160.00 verses $400.00 for a radiator. usually the drivers side will crack around the top fitting for the oil cooling.

Take a flashlight and check around your waterpump, more specifically, the weep hole on the bottom. I had the same problem on my 99' 4.3L. The light came on, I added coolant. About a week later it came on again and I added more. Found a small puddle that "looked" like tranny fluid (this was right after I had my tranny serviced) and took it back to the dealer to check. They informed me that it was my water pump. I was able to see the "stain" from the weep hole when they had it on the lift. Replaced water pump and no problem. If you hit something, check all your hose connections, radiator hose necks, etc.

Be sure to check around your overflow tank. A small crack might not show up when cold but will when warm. I have heard that these trucks like to leak around where the coolant hoses go into the firewall.