Turn Signal problems of the 2014 Chevrolet Impala

When my side detection monitoring system failed a few months ago I took it to a local dealer. They responded telling me that, unfortunately, the design for this sensor module/harness is completely flawed. The sensors are located in the rear bumper, with plastic housing. There is no weather protection, even though these are directly behind the tires and are exposed to all weather - plus I live in IL so we're talking rain, snow, salt, etc. It's two sensors and the harness. I couldn't afford the $1200 repair, so I figured I would just have to deal with the loss of the safety feature and ignore the warning light. Last week, all of my warning lights came on - theft detection, front camera, airbag, stabilitrack, etc. My windshield wipers, turn signals, locks and headlights were all going haywire, and at one point while driving all of my gauges went to zero (no speed limit, rpm, gas gauge, anything) and my heat went out, turn signals stopped working and my headlights went out. Immediately took it to another dealership hoping that maybe my battery (factory original)/wiring might be the cause. No such luck. As it turns out the side detection modules are now corrupting all sensors and electrical systems including my air bags! the dealership confirmed that the side detection modules had failed and were causing the chaos that is occurring with all of my other warning systems, and that my air bags no longer worked. My air bags don't work because of this, nevermind the extreme danger in having a system go haywire while I'm driving! I'm at nearly 100,000 miles so I'm well past any warranty that would cover this, but I have been reading forums and carcomplaints and it turns out that this is a really common issue. The cost of the diagnostics, cost of the repair, and anticipated costs of subsequent repairs is ridiculous considering it is a known design flaw.