Just heater outlets for the rear area. If you were to remove the console assembly which hides the engine cover, you would see a duct running from the top to beneath the floor. It feeds the vents you mentioned.
It is under the console, between the front seats.It is under the console, between the front seats.
Under the vehicle, about halfway back on the drivers side.
In a 2004 Chevrolet Avalanche, the amplifier is typically located in the center console or under one of the front seats. It is part of the vehicle's audio system and is responsible for boosting the audio signal before it is sent to the speakers. To access the amplifier for maintenance or upgrades, you may need to remove the center console or lift the front seats to locate it.
Look under the seats as you can unhook the wire under there for the chimes.
No.
The 1997 Chevrolet Astro EGR valve is located on the top of the engine valve cover. The EGR valve can be access from under the hood. You will not need to remove any engine cover.
Under right front seat
Under the front bank exhaust manifold.
In a 1995 Chevrolet Astro Van, the power window relay is typically located in the under-hood fuse box. It can also be found in the interior fuse panel, which is located under the dashboard on the driver's side. For precise identification, refer to the vehicle's owner manual or the fuse box cover for a diagram.
front of the engine under the crankshaft pulley
Under the front seats
in the front under radiator