Aperture on Canon rebel xs not working

Tyler1297 wrote:

I just bought a used canon rebel xs and i can adjust my shutter speed and iso but i cant adjust the aperture. its not just on manual mode its on every mode i hold the av button and move the wheel but nothing happens, it works for shutter speed but not aperture.

What lens? What aperture value is displayed? Does it change automatically in [green box], P, and Tv modes with half-press of the shutter button in different light/dark conditions?

Apologies in advance if the following are obvious that you already know ...

• In Av mode the aperture is changed directly by turning just the main dial without pressing the Av+/- button. Does it?
• In P mode the aperture and shutter speed chosen should change together when turning just the main dial (Program Shift). But this is subject to the min/max aperture limit of the lens. An f/4 lens cannot open the aperture to f/3.5 or f/2.8 to compensate for higher shutter speeds.
• Pressing the [Av+/-] button while turning the main dial changes the aperture directly in M mode only. In P, Av, Tv, and A-DEP that procedure applies Exposure Compensation (EC) to the settings the camera chooses automatically, and may or may not change the aperture. In the [green box] auto mode it does nothing.
• In Av and A-DEP modes the camera will only change the shutter speed when applying EC.  In P mode it "possibly" could change the aperture, depending on conditions, but usually EC in P changes just the shutter speed.
• In Tv the aperture will change in response to EC, but only if it isn't already pegged at the max or min aperture of the lens attached.