Can't keep my 2004 chevy avalanche on the road!

try a new filter and fluid

Wind will do that...drive on calm days.

batteries will self discharge over a period of time especially in cold weather
however 3 batteries replaced in 6 months raises issues
first question is why would they not charge up on a charger or a run in the vehicle
second question is the battery of sufficient size to run the electronics
have you had the alternator bench tested to check for correct out put, regulator operation and rectifier problems
check drive belt condition and tension
the wire could be a ground wire but I would think that if it is significant then something would not be working correctly

Can only help by putting in a new oil pump as well. I would say remove the heads and check where the coolant is coming from. Bad head or crack in a cylinder wall.

check over all enigne mounts
check select cable /linkages
adjust the safety switch

I would have someone check out the rotors for you.

it is most likey a sticking thermostat it either gets stuck closed or open in your case closed so collant isnt getting to the heater core and all you get is cold air blowing into the truck.
its a simple fix you can either do it your self or take it to a mechanic. now remember there are differnt thermostes so think about the climat you live in and get one according to that

Hello;
Are you getting the check engine light? If so the electronics may have gone out. You may not need a rebuild but you won't know till you pull the oil pan on the transmission and inspect the contents. You may also have lost the neutral safety switch. It is mounted on the drivers side of the transmission. Check those out first and let me know what codes you get.
For Ponchoboy; the clunking and hissing you hear are teminal root causes. Drop the oil pan and if it has a lot of filings and metal it is time for a rebuild.
Hope this helps; Rate me highly;
Rich
RPM Northwest

The front seats I know will work but as far as the back seats they wont because the shape of the truck..

I’m happy to assist further over the phone at https://www.6ya.com/expert/joe_a3369546f8067589

check ur suspension