I represent ASA Electronics, the producer of the JENSEN brand of televisions, stereos, and speakers and the Voyager brand of observation monitors and cameras. At ASA, we strive to provide excellent customer service and product satisfaction and would like to offer some assistance in this matter.
From reading your post, it sounds like there could be a low-voltage situation to the monitor. Please verify there is +12VDC available on the power wire (Red wire) in the monitor's harness. If there is +12VDC at the power lead to the monitor, I would suspect a component failure in the monitor. Please contact your dealer for assistance with warranty or replacement if out of warranty.
I also want to assure you that bright sunlight will not cause the camera or monitor to fail. At most, extremely bright conditions will only reduce visibility, but would not affect the functionality of the system. The angle to which the intense light negatively affects the performance of the picture on the monitor should be minimized to the rising or setting of the sun. If you are experiencing this when the sun is higher in the sky, it is possible your camera needs to be adjusted slightly downward to help reduce the amount of time the camera iris is pointed towards the full sun.
We look forward to hearing back from you.
ASA Electronics - JENSEN, Voyager, iN-Command & Advent Tech Support Team