How do we replace battery in 2005 chevy uplander .. there is a bar that goes across top of battery that looks like it must be removed.

The horn going off is your anti-theft system. When you disconnected the battery, it lost its memory. Number one tip when changing batteries, maintain the power to the car with a charger, or wires to the old battery.

Reset procedure in the link

https://www.justanswer.com/chevy/7rht5-chevrolet-uplander-ls-2007-chevy-uplander-wont-crank-due.html

https://www.google.com/search?q=2007+chevy+uplander+security+reset

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I presume you mean a Service Manual. They are not normally free.
https://www.google.com/search?q=2005+chevy+uplander+ls+3.5+service+manual&

Most things can be found using Google

year make model (what do you want to do)

Here is fuel pump replacement. Search query was
2005 chevy uplander LS 3.5 replace fuel pump

https://www.google.com/search?q=2005+chevy+uplander+ls+3.5+replace+fuel+pump

For starting issues, clean throttle body and Mass Airflow Sensor (MAF) first. If your fuel pump isn't supplying enough pressure, that will cause starting issues. You need to test with a pressure gauge.

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Wiring, schematic, electrical diagrams, torq setting, error/fault codes, full assembly/dissembly, service instructions and a lot moreetc are basic contents of these online books they here on this website https://big-manuals.com/products/chevrolet-chevy-uplander-complete-workshop-service-repair-manual-2005-2006-2007-2008
Must check it out

use a scanner to reset the ECM and immobilizer

ALL TUNES-2008 CHEVY UPLANDER NO START
https://www.youtube.com/watch?v=TnIyKf0JiNU
2007 Chevy Uplander No Start
https://www.youtube.com/watch?v=PN-zlKn5KRo
Starting disabled FIXED!!! Chevy Uplander.
I have a 2005 Chevy Uplander that won't start. The problem...
https://www.justanswer.com/chevy/6jkas-2005-chevy-uplander-won-t-start-problem.html
2005 chevy uplander hard to start
http://www.topix.com/forum/autos/chevrolet-uplander/TALVQR3Q8MKI7M33D/2005-chevy-uplander-hard-to-start

Need to know engine size ..,mileage..,Automatic or shift ...?.Is it full time 4 wheel drive..?

Remove first the battery terminal from the battery (+,-) then remove the bar on top of the battery , loosen the 2 screws holding the under the hood fuse box, lastly loosen the one screw that holds the battery..if you want pictures let me know..

how do I remove my dvd player in my 2006 chevy uplander? I need to replace it and dont want to spend that kind of money to have it pulled out. I dont see any screws or bolts

Raise the hood, and it should be on the right side as you would be looking at it. You'll need to remove one end of the metal bar that goes across the top, and move the support out of the way. Next, you'll need to loosen the bolt and clip that clamp the battery down. Next, remove the negative, then the positive battery leads. Once this is done, you can lift the battery out. Put the new one in, except hook up the negative last.

A simple way is to exmine the relays, if they are all the same,number and configuration, you can swap them around until the fan you are trying to enable runs, then discard and replace the last one you unpluged, or look at a schematic diagram usually in the owners manuel or available at the dealership for reference.