Lost backlighting on HVAC panel on 94 Silhouette

I try this again with a different subject...
I have a problem that I cannot find any info on in the service manual for this van. The HVAC controls no longer light up with the headlights
turned on. I thought I had a burned out light, but when I changed out the stereo, I also pulled out the HVAC control head, and there is no light. How did it light up? Is there a diode associated with the PC board that went out? I couldn't see anything that looked like it would light up on either of the PC boards. Is the only fix for this is to replace the HVAC head? This is really annoying when driving at night. In order to change a setting, I have to turn on the map lights, then attempt to read what I want to change it to.
BTW - I just bought this van a few months ago, and the buttons aren't even close to the other GM vehicles that I have (1996 Sub, 1994 Buick PA).
Any help would be greatly appreciated. If someone could point me to the section and/or page in the service manual that deals with this, I would be very appreciative.
TIA, Bill
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Bill,
GM has many forms of illumination, these days. You may not find a bulb on that pc board. GM also used tiny 1/8" square LEDs to illuminate many button controls. These LED's were of the pc board mount type (soldered, flat, squares/rectangles).
I didn't work for Olds, so I don't know what you have there. I worked for Pontiac/GMC.
If you see any 1/8", clear plastic piece(s), mounted on the pc board, then you might have that sort of LED. These things usually have a tiny bubble lens, to amplify the light.
On the other hand, LEDs rarely go bad. If you found a diode that was burned, I would start there. You may end up purchasing a new control head.
I wish I could give you some more info., but that's all I have.
GMdude
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Bill,
One more thing,... At the dealership level, heater control heads are replaced, and not repaired for a problem. So you will not find any repair information on this subject through GM, or factory service manuals.
Gmdude
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Gmdude,
Could you get me the part number for the heater control head? I would like to look into this a bit more, but I might end up buying one if it isn't too expensive.
Thanks again, Bill
GMdude wrote:

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