The main back illumination on my heater control ('93) stopped working, but the lights behind the buttons are OK. I took the control module out of the center console but couldn't figure out how to completely disassemble it to check for bad lamps. I got to the point where I uncovered the circuit board, but didn't want to break anything trying to disassemble it further. Is this a serviceable unit or is it sealed? Any sugggestions?

 

Well, you should have actually started off checking your fuses.

 

The module has several lamps supplied by the dash illumination circuit and only one does not light, that would be pretty unusual behavior for a fuse.

 

My bad, major brain fart. Comes with working on vehicles all day.

I took a look in my repair manual and found the bulb I think you're talking about. But lets make sure first. You're saying main back illumination for your heater control is out, but the lights behind the buttons still function?

The figure I'm seeing shows that the module has a illumination plate inside. Looks like it feeds almost the whole front, buttons and the light for the bars showing cold and heat. And it also shows 2 bulbs supplying that light.

I need to know exaclty what is working on that. If the fresh air vent light works, if the light at the end of the ***** work, etc.

 

I'll let you know, but I'll have to wait until after dark to be sure . . .

 

The tips of the two slide levers illuminate as does the top portion of the control at the left which allows cool air to come out the defrost vents. The buttons illuminate when pressed. What does not illuminate is the portion in the middle that shows what the buttons and slides are for. It worked for a little while a month or so back, so I know that there should be lights in there.

I got the whole unit out in my hands, but couldn't figure out how to take it apart past a certain point without wrecking it. I'm sure if I could get it apart I could change the lamps . . . even if it involved some soldering.

 

DO NOT TAKE IT APART.

There is a little flap at the top of the unit. Pull that little flap up and you will see 2 little round plastic pieces that have grooves like a screw in them. Those are your 2 lights. Just unscrew them a 1/4 turn and pull them out. You can buy some bulbs from radio shack that will replace them. The part number for those bulbs are 272-1092 OR #7219 Depending on how old the packaging is. They are Micro bulbs.

go ahead and replace them both.

 

Ok, after refering to the diagram, it's showing 2 bulbs are accesible from the outside. By the design of the lighting plate, it looks like 1 is for the buttons, and the other is to illuminate the cool/heat slider. Not the tip, but the blue/red bar.

If you want, I can scan off the page and let you take a look.

 

Thanks, I saw the two things under the flap, but they looked like adjustment pots. I didn't want to mess with them and throw something out of calibration. If you could scan me the page, I'd appreciate it.

ajayhend at hotmail dot com

 

LOL if you found the 2 bulb ends under the flap then why do you still need the diagram?

Oh well good luck...the worst part is getting the whole unit out so its smooth sailing now. Just get the bulbs I mentioned earlier and wire them in and you will be good to go.

 

Thanks for the illustration. I really wanted to make sure we were talking about the same thing. As much work as it is to get this unit out, I didn't want to mess it up.