Curious electrical problem KIA JE

Hello, since January I own a JE 2.0 CRDI 4WD with 140 hp year 2007. The car has hardly any comfort equipment, but a curious electrical problem, which only sporadically expresses itself. Today it was time again. You notice that after switching on the ignition, the ceiling light does not run out. It then also no window lifter works and with the windscreen wiper only the step permanent wipe. Also the washing with wiping water is no longer possible. Water is still on the The rear wiper is also without function. After about 15 minutes of driving everything works again. However, I have already noticed the partial failure of the windscreen wiper during the ride. I first thought of the combination switch as a cause, but since the partial failure seems to be in connection with the other things, I am now rather perplexed what could be the cause. Where could the problem lie? The car is w only a stationary heating, acoustic parking aid at the rear and a new double DIN radio is installed. In addition, a Funk ZV was retrofitted, which however no longer works since the installation of the new radio. Probably the power for the ZV was tapped on a radio plug. Thanks and greetings, Jens