Cold 99 jeep need info

Hi new kid on the block here....... I have a 99 Jeep Grand ltd that I enjoy, BUT Last winter the heated seats then the next season, the climate control stop working. Winter is fast approaching.......I gave my mechanic 500 to repair the climate control( 2 zone) and it worked for 2 weeks and stopped!! It just blows cold air on my side, heat on the other.......The other mechanic says that its usually the heat coil that breaks under the seats and about 250 to repair.. Are they being honest or is there a easier way to fix this???? Thank You Chilly in Philly