I have a 2006 convertible PT Cruiser. A few days ago I saw one identical to mine except it had silver temperature control knobs. I haven't added anything new for awhile, so I went on Ebay and bought some. Well, my question is how do you remove the old knobs? After I had already purchased the new knobs, I found the covers on MRK Group.net. Oh, well. I'm not sure if the knobs can be pulled off like some cars???