I need new tires on my endeavor 235/65/17 are on it now but will 265/65/17 tires fit and work on it????

We won't know for sure. That is going to be a wider and taller tire so you would need to know if it will clear. Check for the forums for your model and see if anyone has done something similar. Alex

Don't modify from factory tire sizes. They may or may not "fit" on the rims and in the wheel wells, but you'll mess up the calibration of the speedometer, transmission shifting strategy and the anti-lock brake system and traction control system. All those components rely on outside tire diameter and tire revolutions to figure out the data needed to operate. It's quite detrimental and has no benefit.

Whatever money you will save on purchasing the wrong size will not be worth the headache!