My AC works fine (1989 190E 2.6) when I'm at speed but warms up when stopped. Basically when I'm on the freeway it blows nice and cold but when I'm in the city stopped at a light, it's not as cold. It doesn't blow really hot air but it feels warm and kind of humid. I haven't taken it to a shop yet. Any advice? Thanks. On a side note, occasionally it blows hot air out of the side vents for a short while and then back to cold.