Topic: Info: Change backlight colors on A/C knobs

[TomatoSoup]

There have been a number of posts on changing the dash backlight colors and usually these hit a roadblock for Heat-A/C controller, since they come with a built-in color filter (amber for Sky's, red for Solstices and <???> for Hummers?).  Similarly, you can't swap a used controller from one make of car to another for the same non-matching color reason.

So yesterday I was messing around with the spare controller I have (subject of another whole topic) and found that it's actually suprisingly easy to change colors, or swap colors from one controller to another.  The color filters are simply clipped in to the cap/face of the three knobs, and those caps are just clipped onto the internals of the knobs and can be popped off easily.

This is a short how-to, but please note that I take no responsibility for you breaking or scratching your controller if you decide to do this!

Tool needed: a thin round dental pick with a sharply bent tip.  Alternatively, a decent sized dressmaker pin, with the tip bent to form an L-shape (and probably small pliers to pull on it with).

This was my spare controller (from a Solstice) and the dental pick I used.  Obviously this controller is removed from the car, but you can remove the knob caps while the controller's still in the car, if you want to.



All you need to do is gently slide the pick down between the rubber rim side and the cap - being carefull not to mar the cap. The rubber & plastic rim has some 'give' but I wouldn't risk doing this with anything thicker - like an electrical screwdriver for example - for fear of distorting or damaging the rim.



Once the pick is low enough in to get under the edge of the cap, rotate it so the tip is turned round under the cap edge - i.e. pointing toward the center of the knob.  Then just pull directly up on the pick to unclip the cap from the knob - do NOT 'lever' it off (even though the staged photo looks like that's what I did).



Here you can see the cap removed, showing the filter clipped into the cap (red arrow) and the two clips that hold it on to the knob (green arrows).  Note: the 'light bar' in the center, that directs and forms the indicator light, is loose. If it falls out, just remember put it back in place before replacing the cap.



As I said earlier, the filter is also just clipped in place and can be popped out to leave white (no-color) or replaced with some color filter material of your own choosing.  Alternatively you can swap filters, or swap the whole cap(s).  Or you can remove the filter and replace the bulbs in the controller with LEDs (and resistors of course) of your own color requirements.

Note, if you only remove the filter and leave the factory bulbs in place, you're likely to get a very 'warm' white light backlight - the bulbs are under-driven for long life.

[Sly Bob]

Good info, thanks TS!     

[DeepBlueGXP]

I did that a few years ago, changed mine to blue

[TomatoSoup]

Sure, NOW you tell me!

[Sly Bob]

I did that a few years ago, changed mine to blue

And you didn't tell anybody?   

 

[Sol Asylum]

He told me and GJ, we just didn't care.  I think there may have been beer involved, we might have been distracted.

[DeepBlueGXP]

I used blue cellophane paper. It wasn't a pretty job so I don't share the not so good mods.  Now if you can replace the incandescent bulb with an LED color of your choice, that would be cool...

[Napi]

Nice mod!

When changing to LED`s, do you need to remove the backplate?

[Kelu]

My light from that knob stopped working, do you think it would be doable to replace the bulb?

[DeepBlueGXP]

Nice mod!

When changing to LED`s, do you need to remove the backplate?

The bulb would be soldered to the back side

[TomatoSoup]

Yes, to change bulbs, you have to remove the backplate.  It just clips on, but there are about 50 clips, so it's a pain!  (I got a few old credit cards and cut them up into ~4 pieces each, then slid them down the sides to release the clips all at once).  This is 2kwk's photo showing the controller, with the back removed. The backs of the three dashbulb holders can be seen (black circle things) - just twist and pull to replace:



As for LEDs, you could solder them, or re-use old dashbulb holders, like this guy's idea:

[DeepBlueGXP]

I noticed today that my AC nob doesn't light up.  I may be doing the LED mod

[Napi]

I noticed today that my AC nob doesn't light up.  I may be doing the LED mod

Same here.
I just wonder if you could simply install some diffuse white LED`s or if you need to install some additional material to diffuse the light...

[TomatoSoup]

The knob material is already a diffuse white, so provided you use a wide angle LED (NOT like the one in the photo above) you should not need additional diffusion material.  But I would test with the cap loosely in place, before you reassemble.

Like this:

[Napi]

I thought about these. 120° and not too powerful.

[TomatoSoup]

They *may* be a little too narrow-angled, but if they are, you can just sand/grind the dome flat.  Don't worry about too much power, you can just increase the series resistor to dim them down.

[TomatoSoup]

I measured the existing bulb bases (in the A/C-Heater controller) for reference.  The bases are 10mm in diameter, and 12.5mm tall (bottom of base to tip of bulb). 

From that and these images, that would make these T4.2 base twistlock bulbs.  Looks like you can buy pre-made ones off eBay if you prefer.





I also measured the bulb filament (unlighted) resistance at 12.5 ohms - not that that helps anyone who's putting LEDs in instead

[Napi]

Nice. I just ordered three T4.2 LED`s in white. We´ll see how they fit.

[DeepBlueGXP]

Was is the voltage going to the bulb.  The t4.2 LEDS are 12v

[TomatoSoup]

As far as I know, it's 12V.  It's a PCM signal from the BCM though (for dimming) so it could be just 10V.  But not a difference worth worrying about.

[DeepBlueGXP]

ordered some blue ones. if this works out.  The kit I bought means I'll have spares for anyone else who wants blue

[Sly Bob]

Kit, or just a dozen LEDs for "x" number of dollars?

[DeepBlueGXP]

20 for 8.99 free shipping

[2kwk4u]

I'm game.  I tried changing mine to blue with cellophane and blue-tinted plastic sheets a few years back when I did my LEDs and gauges, but wasn't happy with the results.

[Sly Bob]

I'm game.  I tried changing mine to blue with cellophane and blue-tinted plastic sheets a few years back when I did my LEDs and gauges, but wasn't happy with the results.

What was wrong with the way it turned out?