Dash Wiring problems of the 1999 GMC C1500

I clicked my 4-way flasher button while dropping my son off at the train station and when I came back it was difficult to press the button back down. After that, the operation of my emergency flashers was intermittent and eventually my rear brakes lights started working only intermittently as well. Now the brake lights do not work and my gm dealer says it will cost more than $500 to replace the whole wiring harness. This is the second failure of this type on this same suburban.