My 2001 tahoe looses power and the lights dim while playing music or lowering windows

Fuel pump

Starter fluid won't work if the starter won't turn the engine over.

Get the battery load tested...it may not have enough juice to start the truck but have enough to light up the lights

check your fuses and battery connections at the starter. Is the anti theft light flashing? If it is that's your problem. Wait 10 minutes insert the key...wait for the theft light to go out before trying to start.

if that doesn't work you will need to get the starter checked...which means you will have to take it off.

change your plugs

ck for leaking injectors

The alternator may charge fine but could drain the battery through a bad diode,have you checked the alt for a bad diode?Disconnect the battery positive cable.Put a regular 12v test light between the battery positive post and the positive battery cable.If the test light is bright you do have a drain,if dim it is OK.A dim light may mean the drain is internal in the battery.If you do have a bright light remove a fuse ,one at a time from the fuse box until the light goes dim.Once dim you have identified the bad circuit.If removing all fuses do not dim the light,disconnect the alt charging wire at the alt,if that dims the light,then you do have a bad diode.DO NOT create a drain(bright light) when checking for the drain by turning on the key or opening a door/trunk etc.
Also,do an overnight battery check by disconnecting the battery overnight,if things are fine the next morning after the battery was disconnected then it is a drain in the vehicle,if the battery is dead even after being disconnected overnight,,then the battery is bad.

CHECK BATTERY CONNECTIONS AND BATTERY CONDITION

Below are the removal procedures for your vehicle's front inner door panel.


On models without power windows, remove the snap ring retaining window crank handle. Remove crank handle and cover plate.
Remove lower door frame bracket garnish. Using a screwdriver, remove inside door handle bezel. Remove power mirror control switch and disconnect harness connector.
Remove armrest panel. Remove 6 screws. Pry interior door panel loose from door.

Is it any window or one certain window. I would still get my battery and charging system checked anyway. If it is one certain window you might what to have it checked due to it pulling alot more power than the others. Blinking or kinda lightly flashing headlights is a sign of an alternator problem. I would also check my battery connections.

I had the same problem with my 1999 chevy dually. I tried everything and finally after a lot of lost sleep headaches and money we found the injectors were leaking. It was expensive but it starts right up now.