Windshield Wiper/washer problems of the 2003 Dodge RAM

I took my '03 Dodge Ram to mcpeek Dodge dealership in anaheim, CA for warranty windshield wiper repair work. The truck was in perfect condition except for the wipers. Later in the day the service person called me to let me know the work was completed, but "by-the-way, we noticed your check engine light was on - do you want us to check this out?" I replied first of all the light was not on when I brought it in and second I was not going to pay any diagnostic fee and I expect it to be corrected when I pick it up. It was not corrected and delivered back to me. Obviously, dealerships (especially big 3 manufacturers) are trying to recoup losses through fraudulent / unnecessary service due to the minimal margins and volume of sales of new vehicles. I am a mechanic and understand the sales pitch - while I was sitting in the waiting room I felt sorry for a little old lady that the service guy preyed on. She just wanted a oil change, but ended up having her brakes inspected and probably replaced only because "he noticed they were squeaking". Anyway back to my story - it took me all of 5 minutes when I got home to pop the hood and find a wire to the air cleaner sensor that the mechanic had disconnected probably intentionally since this has nothing to do with the wipers. The check engine light went off. I found out that the management at this dealership has instructed the staff to make sure to up-sell every customer and make sure some other work is found besides anything that the vehicle is brought in for. That's fine if something is needed, but to intentionally damage a vehicle or replace parts unnecessary to make more money is just not right. I saved $150, but am steaming mad! mcpeek Dodge is a crook. I will never by another vehicle there again and never service there.