trailblazer

I have a 2004 trailblazer and the lights have been dimming ever since about 5000 miles. they have updated the code changed plugs and replaces the alternator. I am still having the problem. Now it is having trouble shifting out of 1st gear when first started. I am trying to turn it in on the Lemon Law. If you have any help let me know. VERY UNHAPPY CUSTOMER