My 1999 Blazer 4WD is psycho. First, I get all these trouble codes P1035, P0452, P0453, P1870. Second, the 4WD panel (auto4wd, 4wd hi, 4wd low, 2w, neutral) every light comes on as I am driving (driving feels a bit sluggish) then all this clicking (trying to engage?) along with the panel lights on/off, and then the service 4wd comes on then off. This has also happened as I sat in a drive-thu in NEUTRAL! Can anyone help me figure this crazy thing out? I love my Blazer and I don't want it to DIE

 

do you notice the lights coming on if you turn an accessorie on? i noticed when my battery and alt went that when i would turn anything on all my lights would come on and i would feel super sluggish.. its a starting point