Ok, I replaced the heater core in my Durango, at the same time I put in a new headlight switch because my old one had a rattle in it upon removing it and I knew this wasn't normal, I also replaced the heater/ac control panel because that also had some rattles in it (197k) so I figured it was due. I thought I put everything together correctly but now after getting it all together everything works except the headlights... park, signal and emergency flashers all work but when I turn the headlight switch on to the first setting the interior lights go dim and when I move it to the second setting the lights stay dim and the emergency flasher arrows light up on the dash but they don't flash just stay lit? The only thing I can think of what I may have done wrong is that there is a ground wire on the drivers side of the dash that I may have connected incorrectly but as much thinking that I put into this I have no recollection of where this ground wire is suppose to be connected? Any ideas?

 

Sounds like either a bad ground some where or a bad switch (yes, they can be bad new) Usually a ground wire can be attached to any clean metal surface...

 

sounds like there might be a short in the switch. try putting the old switch back and see if the problem is still there.