Full power loss
 

Someone please help, I've got no idea where to begin with this so I'll lay it all out and hopefully someone can help. I went out to start my 2000 4dr.4wd.blazer and got no response, no click, no lights nothing, jump started it and let it run for a little bit then turned off, went to start again and nothing, this time I hooked up the jumper cables and sat in the truck, I started hearing clicking for behind the pass. Kick panel. Feeling the tccm confirmed that it was what was clicking. As my batt. Needle hit about 12v I tried to start it and all lights and gauges dropped power, nothing. I disconnected and reconnected jumper cables and batt gauge rose and the truck started. Again when I turned it off and tried to start again, lost power now the tccm is clicking as well as the area where the bcm is located. Someone please give me good news, computer problems are the reason I had to scrap my last blazer...if anyone needs more info please ask

Have you checked the fuseable link, all the grounds, power wire to the battery everything clean and corrosion free, is the battery good?

^^ X2. Take the battery cables off of the battery, and remove the bolts from the cable eyelets. Clean everything with a wire brush and put it back together making sure the battery cable bolts are clean & tight.

I'll try all of that tomorrow including taking the battery to autozone for a test. Never considered it being something that simple, hope it works

Always try the simple stuff first. A good visual inspection is invaluable.