Okay, the two Pyle video cameras has been very disappointing: the passenger's side unit has already failed; probably due to the heating problem I mentioned above.
I have already replaced it with what seems to be a better video camera -- it does not have any obvious problem like the heat, and the lens angle is less wide. I have not driven with the newest (third!) camera yet, but it is rated down to 0.5 lux which should be quite good in the dark.
Amazon.com: 1/4" OmniVision CMOS 420 TV Line Color CCTV Rearview Camera - Back-up Your Vehicle Safely!: Electronics