[grausj1]

Have pulled several trailers with no issues. Now I have tried two different trailers and the instant I hook one up the right rear break light comes on whether truck ignition is turned on or not. ANY ideas? Checking the pigtail that lead is hot +12 all the time whether on the flat pin connector or round.

 

[bsil12]

im assuming then that youre talking about the 7 pin rather than a 4 pin... If i remember correctly one of them is +12v all the time. Its to charge AUX things... maybe your plug is wired wrong, or the trailer is wired wrong. I would verify your truck because its more important that that is correct rather than the trailers... otherwise you'll have issues with most trailers. http://www.chuckschevytruckpages.com/images/7pintrailer.jpg might help you trace it.

 

[grausj1]

Thanks. Wiring is factory and used to work. Tried on different trailer (3) all the same. Checked right running light pin on plug and is always on. It is same for 7 and 4 pin. Ground is good. Checked also using voltmeter and cheater boughttest plugin. Replace F C MY module also as in known issue with Dodge. No luck