01 pontiac montana 3400 motor no power going to starter, have replaced starter and checked all fuses and breakers. checked at starter with test light ,power on one side but not other. nothing on key when engadged to start

What exactly does it do when you turn the Key? Are there any dashboard lights staying on that normally go out when you turn the key to position 2?
Does it do absolutely 'Nothing' with the dash lights staying on? Does it do nothing but the dash lights go off?
Dash lights go off and you get a 'Clunk' noise?
Absolutely nothing suggests security system or the actual ignition key/barrel. This often has a light on the dash shaped like a key. Nothing but the lights go off could be the starter solenoid. Lights of and a 'clunk' could possibly be the starter itself.
The solenoid will be bolted directly to the starter motor. It's the smaller barrel shaped section on the side of the actual starter motor.

It's not a fuse problem , all the other windows work ? One Circuit breaker powers all windows . Probably the window regulator is bad or the switch or the motor . Pull the door panel off the driver door an test the electrical circuits . Could also have wires broken inside the body to door flex joint (black rubber boot )
How To Diagnose your Power Window Problem Is the Switch or motor bad

Check battery and connection.

It could be a main computer or it could be some of the big fuses inside fuse panel

There is an ignition/starter switch on the left side of the steering column that activates the starter solenoid.

PUT A BREAKER BAR ON ENGINE CRANKSHAFT BOLT AND SEE IF YOU CAN GET THE ENGINE TO TURN OVER BY HAND,IF IT WONT TURN, SOUNDS LIKE SOMEONE SOLD YOU A EHICLE WITH A LOCKED UP ENGINE. GOOD LUCK!!!!1

well if you have power for up and down at the plug then it isnt a relay or fuse issue or you would have no power, did you just replace the motor only? it might be the regulator also, if it went down and wouldnt go back up then thats probably the issue a failed window regulator and thats the assembly that attaches the window to the motor and allows the motor to move the window

Most likely the window motor/regulator assembly has gone bad.Check for good fuse, if good pull out the switch and make sure you have power to it, if you do then remove door panel and test for power at motor, if u have power but motor won't work replace. Suggest replacing the regulator assembly as well because the cables often fray and cause problems as well.

using a test light on the rear blower motor wires ,turn it on with the switch,and probe the wires for power,if you have it there then replace the motor

aye lower intake gasket 50-60,000 mi
but i like the 3400 its a strong engine.