instrument cluster is not working

Instrument cluster (speedometer, Tachometer, Break & ABS light) is not working while driving.
My video for my 2009 camry 2.4 LE is here (https://www.youtube.com/watch?v=kwMBLAEx29w):
https://www.youtube.com/watch?v=kwMBLAEx29w

Toyota service center asked $6000 to replace wire harness and PROBABLY electronic control unit.

I found some posts, but the answers are not that clear to fix it.

http://www.fixya.com/cars/t15246806-2007_toyota_camry_abs_light_brake_light

http://www.justanswer.com/toyota/6ru2n-exact-sme-problem-one-previously-posted.html

Any comments would be appreciated.

I have seen really weird instrument cluster behavior when the alternator is bad. It can still charge the battery, but have strange voltage fluctuations or some other bad output characteristic.