Dash lights are out at climate control area on our 2005 lesabre limited. Also some are out on the steering wheel controls.

http://www.appsforpcx.com/mini-militia-on-pc-windows-mac/

I found this link for steering wheel. Don't know if this is what you need? I will look for the wiring diagram.

http://www.silveradoss.com/forums/topic/56992-5-steering-wheel-control-light-fix/

These are actually the bulbs that have went bad. It would be quite expensive. I have a 2004 that has done the same thing. No lights behind any buttons any more except the ac heater controls I replaced last year.

use driver information center button ENG/MET: Use this button to change the display
between English and metric units.
dic buttons are onleft hand side of dash closest to steering wheel.
Cheers!

Look for a iluminated fuse,or inst.lps,fuse,try moving the dial,or knob to brighten the instrument lighting.

First disconnect negative battery cable.
Then go behind steering wheel, there will be about 4 screws to remove, then the steering wheel can easily be pulled apart with no worries. Then unscrew unplug and pop out your controls.

look behind dash panel under steering wheel,mounted to dash brace. if 4-ways work,flasher will 'click'.

The battery. Get another one from a salvage yard.

check the fuse box and under hood ,check one by one with the climate control on and radio lights on , and you will see when the radio its off or on.

I finally replaced the Backlights, using a guide from a person at www.answerbag.com
who wrote:

(i've got an 04 limited. i just soldered in new bulbs for the lighting controls panel (5 #272-1092) and the digital HVAC panel (1 #272-1092 and 5 #272-1154). steering wheel control bulbs are next. )

Just buying a cheap Used one may be the best, if you are not good with dis-assembly and soldering small electric bulbs
Depending on the style you can get a Used One from an online junkyard for 25-50 USD
Check LKQonline out..
http://stores.ebay.com/LKQonline

The most difficult part is getting the Climate Control Module out of the dash, to make the soldering new bulbs repair. The wood-grain Bezel needs to come off, BE CAREFULL, its long and flexible and can crack easy if the wrong pressure is applied or its cold outside or cold in the car cab. Its held in the dash with GM friction clips ( pain in the %$#) and 2 Phillpis screws behing Glove Box door. I worked the pull- pressure from the A/C vent on Right, left-ward to the center, and from Steering Column right-ward toward the center. Once the Bezel is removed, the Climate Control Module is seen, with 4 push-tabs on each corner. BE CAREFULL pushing in the tabs....I broke off one as in pushed too hard. Pry out Right side while pushing 2 right-side tabs gently together. Repeat for the Left Side, while pushing 2 left-side tabs together gently. The Climate Control Module should pop out. Use a 3/8inch Nut Driver to remove the headless screws that hold the Climate Control Module PushButton plate to the box. This will expose the Printed Circuit Board for solder replacement of the Bulbs.