I always spray alitle WD40 into the connector and move it all around when plugging in... That cleans up the connectors pretty good for me. The exports on here will say to use Contact Cleaner Grease Lubricants..
I also find it handy to have one of these 7-way adapters aorund when you are having problems with lights etc... This plugs into the truck side and you can see the small LED's work telling all is OK form the truck side... Got mine from AMAZON...
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Some folks use stretch rope to keep the trailer cable from being pulled out of the 7-way connector on the truck...
Roy Ken
