If still towing with a Honda Ridgeline as indicated in your profile, this forum / thread may be of interest (I'm a former Ridgeline Owner
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This Ridgeline Owners Club forum thread touches on parking sensor alarms when towing. I suspect your issue is the 'obstacle proximity alarm' related to the rear parking sensors when the trailer is hitched, and yes that can be defeated with a switch on the dashboard. IIRC that system defaults to "On" every startup so you may need to disable it each time you restart the vehicle while towing.
Hope that helps, good luck!