OK let's see if this can stay up here without being deleted....





Finished it last night, lots of fun!!

 

As I said in the earlier post that was deleted, it looks great.
Now if LV_2_XLR8 could repost his information on the reason why the HVAC is brighter than the radio, and his idea of countersinking the LEDs; many others can learn how to do this modification; whether they want to or not is another matter.

I still have go decide how to dim the HVAC to be more in line with the radio.

 

Bought mine with white guage cluster installed that goes from green to blue. Planned to eventually pull it out. Like the blue but it does not match the rest of dash lights & will not dim with other dash lights so I can use HUD only at night. Now that I see this I am rethinking removal. Looks good...

 

 

Some pic of my work 2

 

What ohm did you come up with for the HVAC to dim down to the radio brightness?

 

Haven't done it yet, probably not until next weekend, still waiting for my replacement DIC holders. Going to try a 6K ohm resistor in the yellow wire from the BCM to pin C16 of the HVAC. (Besides, I have to install two new Dana Axles, in my Jeep this weekend.)
I have ordered a 12 VDC power supply, so I can test it out on the bench prior to installation.
To dim down the left DIC bulbs, I'm going to play around with those blue rubber boots that were on the previous bulbs, and if that doesn't work, get out the black paint, and if that does not work, it is another resistor inline to the left DIC.
The HVAC and left DIC are way too bright at night and in fact, can be seen during the daylight. Backlight should only be seen at night.
I'll let everyone know what the resistor does, or does not do.

 

Okay, let's try this again...

I'll begin at the beginning. (Ah yes, the "Yellow Brick Road" theory) I decided to do mine in red. Initially, I decided that rather than to place a resistor with each LED in my radio, I would find the feed wire and just put one single resistor in that circuit. Makes sense, huh? Well, that's what I thought too.

There are actually two circuits that feed the filament bulbs in the radio and that in itself is no problem. However, after soldering all the LEDs into the circuit board and testing my single resistor theory, (not to be confused with the single bullet theory) I discovered that even the 1 watt resistors I substituted for the little 1/4 watt resistors, that came with my LEDs, were starting to smell and it become extremely hot. To make a long story longer, I began increasing the resistor wattage until I ended up with two 12 watt wire wound 12 ohm resistors in series for each circuit and they still get pretty hot. I tie-wrapped them to the bottom of the radio to try to keep the heat as far from the rest of the components as possible. So far so good, but I was reluctant to share this revelation with the group until I had enough history to say there's no problem, so take it for what it's worth. It did make the radio conversion much easier though. No resistors to deal with and no plastic to cut.

Now on to the HVAC issue...

I did some calculations and testing yesterday and discovered that 6K resistors will give you the 1.85vdc that you have in the radio, if you used the resistors that came with the LEDs. The issue with the radio is that there's only 9.2vdc supplying the filament bulbs as opposed to 11.8vdc in the HVAC unit. I chose to brighten the radio, but if you wish to dim the HVAC instead, then 6k are the resistors to use providing there are no other variables. As I pointed out yesterday, there is no diffuser film in the HVAC unit and also the LEDs are farther away from the buttons, so this will not guarantee the illumination intensity will be the same. I also found it better to leave the original filament bulbs in place each side at the bottom of each ****. This allows you to still retain the red and blue effect of the hot/cold arrows beside the *****.

The LED configurations...

After much experimentation, I discovered that there are two shapes that will accommodate all the requirements you will need to maximize the effect of this conversion. I began by putting the LEDs nose first in a 3/16 inch collet in the lathe and turning .030 off the base. This will remove the little flange and allow you to put the LED in the collet with the nose facing outward. (If you don't have access to a lathe, an electric drill and a file will probably accomplish the same result) After trying many configurations, the two that worked the best were achieved by turning the nose to a 45 degree point (90 degrees overall) and slightly rounding the point. This will give you a nice fan of light with no hot spots and works well in most of the HVAC buttons. The other configuration was achieved by using an 82 degree countersink and plunging it into the nose of the LED, stopping about 1/16 inch away from the diode itself. This gives you more of a peripheral lighting effect, much the same as the original filament bulbs, only with less light emitting forward.

Sorry, I never intended for this to become this long, but you guys asked for it!

Hopefully this will help those who haven't tried this yet. It sounds like a hassle, but I'll assure you, it's well worth the trouble.

 

Possibly next weekend I'll get around to trying the 6K ohm resistor in the HVAC backlight power circuit (yellow wire) and see what the results are, then post it here. Hopefully, it will get it close to the intensity in the radio illumination.
As for the original bulb, Rob came up with the idea to use white LEDs on each side of the *****. This allows the red to be red, and the blue to be a normal shade of blue on the temperature color bands that surround the *****.

Did you do the DIC switches too? If so, did you notice any differences between the illumination levels of the left versus the right? (Left being brighter than the right.) I have to do something to dim the left, but waiting for some replacment plastic holders for the LEDs.

If a long post is informative, it is great so no apologies required. You came up with some great ways to make these projects easier, and your information is helpful for those of us who have done it one way, and need some adjustments to level the lighting.

 

I have done the entire interior, including the DIC controls and I also found the left bank of switches to be brighter than the right. Unfortunately, I had completed the conversion of the DIC switches prior to doing the radio and HVAC unit. Consequently, I didn't have the information I needed to configure my LEDs correctly. Also, I would have benefitted from knowing that 3mm LEDs would work better for this application. (these bulbs are considerably smaller, which should have raised a red flag to begin with, DUH!)

So here's my plan...

I have ordered 3mm LEDs for the left side DIC buttons and I will configure them with the internal countersink modification. This will give me mostly peripheral light, which is really what you need in this instance. Since there are four of them, I suspect this will give me a slightly less brilliant, but more even light dispersion. Also, they aren't quite as bright to start with, so this should help too. I will update everyone after I recieve and install them, hopefully with some photos.

Stay tuned...

 

Hey, thanks for the "long" post, it's exactly what I was asking about! As for the HVAC, I'm debating whether or not to redo the board with the larger ohm resistors. In order to correct the "farther back" position of the LED's in the HVAC, do you think that just extending them will change the result? I'm gunna go out an buy some resistors now and kick myself in the butt the whole way there knowing I'm going to redo the project... damn...

thanks again, Rob

 

So which wires are the + on the radio and the HVAC??

 

I did 3mm on the left and 5mm on the right. Also broke one of those dang plastic holders and have since ordered a few...just in case.
Next time I do this, I'm going to have my 12 VDC power supply.

 

I'm duly nervous about posting links after yesterday, but if you do a search, there are a couple of recent threads (one by SpdKilz and the other by CUlookin) which will illustrate both for you.

I was remiss in thanking these two guys for guiding me through this task, so I'll do it now... Thanks guys!

 

Do you mean the backlight dimming circuit wires in the harness at the connector to the HVAC and Radio? if so, here goes:
Auto HVAC: Yellow wire that comes in on Pin C16 of the large connector. This system works the old fashioned way, a dimmer switch dims drops the voltage to the backlights dimming them. The dimmer switch also signals the BCM for operation of the radio dimming as describe below.


Radio: The radio in the Vette does not operate as other radios in most other cars. It is totally controlled by the BCM. Most cars have a constant hot for memory retention, a ignition run hot for starting the radio, and a dimming circuit from the dimming switch on the I/P. The Vette radio works like this:
Orange wire to pin 10 of the thin black 10-pin connector is a hot wire directly from the battery (via a fuse). This circuit is used to retain memory and to power the radio.
Pink wire to pin 6 of the same black connector is a radio signal turn on/off. I believe this signal comes from the BCM, but cannot find reference to it in the GM schematics. No matter where this signal comes from, the signal wakes up the radio, and it pulls power from the one orange wire.
Orange wire to pin C16 of the thin gray connector is a class 2 serial data line that is used to control the dimming feature of the radio's backlights.
I believe these two connector are stacked together at the back of the radio, can't remember.
The other two connectors, natural color, one squarish and the other thicker than the two mentioned before are not used for power to the radio.

 

I think the main gripe was it linked to his site where he also sells stuff.

I have done tech tips on this, and if you click my profile you can check some of them out.

Looks good (for the second time ) Nathan.

Carleton