Call Maxxair. It's a known problem, the fix takes about 5 mins once they send you the part. You'll have to go up on the roof to replace the part but it's super easy.
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2014 Redwood 38BR, Fulltiming
2013 Ford F-350 CCSB 6.7L 4x4 SRW, B&W Companion Hitch, Air Bags