When the key is on, the fresh air blower on my 75 2.0 is always on high speed. It worked correctly until a couple days ago, now won't shut off regardless of the the position of the top fan lever. Any ideas out there?

Confirm that it is the front blower box for us. Switch is on slider contacts that rarely fail.

Mark, it was the front blower and after removing the ashtray and looking in there the brown wire came off the connector and was making contact without the control level being moved. it's all cleaned up and working as it should now. Thanks for the response.