Evidently, cyclometers and sun do not mix well. Went for a ride yesterday, and left the bikes, with cyclometers on them, in the back of my truck, while we took all the gear in, took the dogs down the street for a walk, grabbed some ice water, etc. Was probably around 20 minutes they sat there. Upon unloading the bikes, noticed one of them (an inexpensive wireless house brand) had all the display showing, every function, zero's for all of the numbers, whatever could appear on the screen did appear on the screen. Was hoping it would work after it cooled down, and luckily, it does. So, don't leave your cyclometers out in the sun for long periods of time. The only thing I can figure is that LCD's must work by heat generated by electrical impulses?? Just wondering, figured that the LCD's being heated up brought them up on the display.