I am at the point where I am about ready to start driving my 1992 190E after 2 years of storage/fixing. The antenna on the car always worked flawless. I replaced the mast back when I bought the car and never had a problem.

Now when I turn on the radio, the antenna won't come out. I removed the antenna from the car and opened the cover. If I turn the motor by hand, the antenna goes up. If I plug the antenna back in the car, it automatically resets by going down to the lowest position. Therefore, the motor does work. I have power to the red wire. I also have power to the blue wire. I don't know the voltages as I checked with a test light, but I can check back later. My guess would be that the head unit (aftermarket, but it worked before) doesn't send the signal to lift the antenna, but that is the blue wire and I have power to that wire! Anything else to check?