So I just bought myself a hummer for my birthday! One thing I noticed was the heated seats were not working. Would that be a quick fix?

 

probably not unless some disconnected a seat heater.
usually the seat warming pads go bad and cause the fault. they are stitched into the leather seats and GM does not sell the leather any longer.

 

You can find new leather seatcovers on ebay from a place in TX they are outstanding and take a couple hours to remove/ replace seat heaters/ new leather covers & reinstall. Its an easy job (the original were stitched into the leather cover- these will lay down on the seat foam pad & then you cover. Works the same & looks the same after leather installed. The seat heaters I used are were Dorman 641-105 but I bet these would be the same and are inexpensive. If you are on a budget - buy these on ebay & you can simply unplug the harness under the seat & plug in the new replacement to see if functioning before spending money on the leather seat covers &your 2 hours to install (seat is literally 4 bolts & a couple connectors & lifts right out of truck- they use a female torx but i think a certain socket also may work on those torx heads)...- https://www.ebay.com/itm/30582945772...QaAq-dEALw_wcB

the leather seat covers you can get here (I am unsure of the quality on these but this gives you an idea) Mine came from an upholsterer in Houston and they were exact
:https://www.ebay.com/itm/26571976329...KW2GWHQPNJ8ZKH

mine came from this company- they were perfect and install is super easy (Richmond Auto Upholstery in Houston TX)-
https://www.ebay.com/itm/32256135069...Bk9SR8q9_8ykZQ

 

What everyone else said. Here's a great video of how to do the work.