Dude in my town had a mid-60s Telefunken van. I was maybe 12 years old (late 70s) when I'd see it driving around. It was lost on me, but I appreciate the memory.
I'm not sure where you were, but what you saw was almost certainly a service van with the Telefunken name and logo because Telefunken was one of the major brands of hifi radio consoles and table radio sets at the time. As the availability of FM radio increased in North America, so did the popularity of the living room hifi console. FM Stereo broadcasting furthered the boom. When community cable tv companies began to include FM Stereo stations in their services, often with stations normally out of range of home antennas, there was a further sales boom. As with all major brands, Telefunken hifis came with a record turntable and AM/FM (later FM Stereo) radio band receiver, but Telefunken also included Short and Long Wave bands as standard features. Major North American brands integrated TV sets into their high end consoles while Telefunken remained radio-turntable only. Eventually the market demand for large hifi consoles died off and now they are collectible relics, boat anchors, or landfill.