Steering Column Repair: signal lights and more, turn signal switch, left turn signal

Question
Have a 1999 Chev ASTRO, with tilt wheel, 1st symptom was when left turn signal selected, the right also blinked dimly, did the usual, inspected wires, connections, etc, also noticed that when the RH signal was on, the radio display, overhead console display and the odometer display blinks, audible alarm comes on with the 4 way flashers on and finally, when I step on the brake pedal, the dash, radio and exterior parking lights come on. Early on it appeared that I had a bad turn signal switch (multifunction), replaced that, had all the same problems plus the engine would not turn over, put the old switch back in, van started, returned the switch, reassembled the column, and, of course, the van now turns over and starts only part of the time and I still have all of the original electrical problems. The van has keyless entry but hasn't been used in years, never in 10 years, had a starting problem with the vehicle. I ensured that the new multifunction sw was identical to the old one in every way before I installed it, I'm stumped! thank you for your time.

Answer
Hello Calvin:
In reading all of your problems over (and I must say, a very good job of describing them...thank you) it sounds to me like you have a ground problem in the vehicle.  What you are describing is not a steering column or multifunction symptom, but an electrical problem that encompasses many circuits including the turn signals.
I would start by looking at the small ground connection from the battery to the body, then the large ground cable to the engine and finally the ground straps from the engine to the body.  Some of them will be rusty, corroded or missing and that is where the breakdown is occurring.  The power in any given circuit has no way to get back to the battery so it tries to get back through other circuits causing you to experience the feedback.
Lastly, I would also check to make sure the charging system and battery are both operating properly and holding a charge.
Let me know what you find..I'm hopeful it will be an easy fix

Good luck
Doug