Ian: Thanks for the answer. In fact, the light bulbs are OK and they donīt heat up. The red hoses I mention are (I suppose) air hoses, since they donīt seem to have water. If disconnected, the knobs donīt heat up, even with the lights. if connected they heat up. I presume it may have something to do with heating up for cold wheather, before the water heats up, but I could not figure it up yet, since in hot temps it also heat up very much

thanks again for answering