Why do you want to replace the horn? If it's not working check the relay in the fuse box under the dash on the drivers side.
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Why do you want to replace the horn? If it's not working check the relay in the fuse box under the dash on the drivers side. Here's the relay switch: http://www.autopartswarehouse.com/details/QQChevroletQQCavalierQQAC_DelcoQQHorn_RelayQQ19821999QQACD1776.html