OneWire command dims LED pin 13

Strange but true. I use a 3V3 ProMini and latest library : OneWire ds(7);
Just having the command in the executable code, the onboard LED13 is dimmed very low.
Even when the LED13 is lit (with a delay) before the command is executed!

Please post a complete sketch that shows the problem, using code tags when you do

What device is using the interface and how is it connected to the Arduino ?

Solved : After minimizing the code it was clear that two lines of code seemed incompatible and caused the onboard LED13 to be dimmed. Finally I found that a variable was defined as byte and should have been int.

You should post codes so that the readers can figure out how the device (the onboard led) is being affected when the sensor is connected at DPin-7.