Do your dash lights dim when you turn your turn signal on?

2007 JKU Sahara

I am pretty sure it has always done it, and I have upgraded the battery ground, alternator wires to 0 gauge. New alternator as well.

 

I have never experienced this, nor seen anyone else talking about it. I would be down the same line of thinking you are though, with the idea being a bad ground somewhere. I've dealt with bad grounds on a different vehicle, and it was the most frustrated I think I've ever been working on a car.

 

where would you start checking for grounds?

 

I just had to replace the turn signal lever on my 2007 because the dash light control was erratic. That is, it wouldn't dim the lights, but it would cause the interior dome light to come on at different places than usual. It's about a $90-100 part at your local auto parts stores, and a five minute job once you figure out how to get the shroud apart. Also, FYI, your OEM alternator in a 2007 JK was 160-amp. Replacements may be the lower 140-amp used in later model JKs.