Have replaced a 2 1/2 year battery with new. Didn't solve the problem, took to local mechanic a draw-down in juice was noticed, caused by a fault in Left Side Window/Lock switching unit, replaced that charged battery and to quote, it's FIXED. Uh huh, right next day back to the shop he has gone over the vehicle from every angle and cannot find the problem. Truck is 2000 Blazer with 68,000 miles driven only a few miles a month. When I jump it off with my Ford truck after hooking cables up with Ford running it takes about 3 minutes before enough juice gets into the battery to light the hood light that's how dead it gets. Anybody got a hint of what's causing this?

 

Check the vanity mirrors on the sunvisors.