We just got our hands on a '07 3500 Express. This had the separate manual climate controls for the front and rear. Both have a burned out bulbs.
I can get the rear controller out. That is just press fit into the head liner.
I do not know how to get the main controller out.
My questions are.

1. How does the main climate controller come out from the dash. Does the entire dash surround have to be removed? Any one got pics and such?
2. What size/type bulbs are these? The Sylvania/Osram guide does not list them.
3. The fuel gauge is also out. Does the cluster use the same bulbs? I feel compiled to do them as well.

 

Ok I went to the dealer. They were next to useless. I have never been told by a dealer they could not sell me something. I was surprised when I was told they could not
a. provided me with a replacement bulb for the rear climate controller.
b. Could not provide me with a part number.

I was instructed to visit united radio service. http://unitedradio.com/automotive/
The very nice person their took in the back and found no Exact replacement.
He stated that "the dealers always send people here".

Apparently, the bulb he put in there is # 74 bulb. as it was inscribed on the replacement.
It isn't the right brightness, but Damn near close.

Bulb #74 For Rear Climate control, MY2007.