maybe dirt on the camera lens? maybe wire connecting loose?

I installed a unit that has radio, bluetooth, cd, plus this backup camera, which is really the most I wanted.  It was a terrible installation as product has very little instruction guide for wiring.  \

It's been working fine since Feb this year.  it went out only once when truck was parked at a spot when temperature was over 100 degree.  

so perhaps replace it?  Here is the one I bought for $40.