03 electrical problems

I have an 03 trailblazer and I have had it in the shop at least six times. The service 4wd light comes on a lot. I also had to have it towed because you could not shift it out of park when I started the vehicle.
Last week the service brake banner came on, then went out.
I also could not start the vehicle, had it towed and the dealer said the ignition switch was bad. Dealer said the intermittent lights were caused by the faulty ingnition switch, Sounds like he is feeding me a line. Has anyone had these problems??

I have had some of these problems in my 03 TB EXT. Dealer fixed them by uploading new software abd cheking/updating the servos and relays under the rear seat. Have them check for software upgrades.

I have seen many phantom electrical problems including, no start, Inoperative HVAC and others caused by faulty ignition switches in these trucks.
There are also a couple grounds that will work themselves loose and cause some problems.