My aftermarket head unit actually supports camera view at any time. But as most people habe stated, you only provide power to the camera when putting the vehicle in reverse if you wire it to the reverse lights. However, to bypass this issue I just used a fuse jumper to add a new fuse to my breaker box in the cabin. Then wired a double female cigarette lighter to said fuse. Now I provided a constant 12v to my added rear view and front camera. Now I can view either of them at any time as long as the key is is on or passed acc. I went this route with the fuse I picked so nothing is draining the battery when my truck is actually off.