2000 Other Oldsmobile Models please help

I have a 2000 Olds Sillouette that is giving me fits with electrical problems. Step on the brake and the flasher indicators light up. If the lights are on the left signal blinks very fast. But, the worst is when using the cruise control and you turn the left signal to change lanes, it disengages the cruise. My local dealership said it was the turn signal switch and wanted $750.00 to replace it. I bought a new switch and changed it myself. Very easy. Anyway, I finished about an hour ago and it did not fix the problem. Glad I didn't let them do it. I welcome any help you can offer. Please help, I am desperate.
Thank you,
Randy Wylie