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The wiring from the body to each harness is very common for breaking, especially around the lower ball joint.
If they have a scan tool can they tell which side the issue is or what the code is?
Start looking at the wiring aroudnthe ball joints. I have seen these break MANY times.
The harness end is easy to replace, takes about 20 mins, and is about 40 from GM. IT is only the plug and pigtail with about 18" of special wire.
After that we will need codes from the system, but I have confidense this is the issue.
If the harness does not work, yes. Clearing them will not be an issue. If after the test drive the ligth is on, then the issue remains. It does a self check that runs every ignition cycle and when you get past a certain speed, usually 5 mph.