You can also pull the cluster out using a two pieces of a coat hander with a bend in the end of each one about a 1/4" long. Once it's out you disconnect everything and can pull the entire cluster out. You may have to do this depending on which bulb is out. If it's one of the bulbs on the lower part you can probably reach them from underneath like stated previously, if it's on the the bulb on the top you'll probably have to pull the cluster.

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