2003 Denali: Rear HVAC controls illuminated?

[BigFat]

Hey guys... my buddy has a Canadian model 2003 GMC Denali. It has the rear seat entertainment screen/dvd package, as well as rear hvac controls. It's difficult to see at night because the buttons on the controls don't illuminate. My question is, are they supposed to illuminate? And if so... is there a common reason for not having lights?

Thanks.

[Tahoe 400]

They should be illumnated, the bulbs might be burnt out or there is a break in the illumination wire to the controls. Those bulbs are not replacable so you would need to get a new hvac control. The illuminateon wire should be an orange or orange/black wire so you could test it before getting another one.