HVAC LED conversion

[guumbah]

To expand on chuck16's original post with a little more detail, and for kenwood guy, here is a little instruction on how to convert the HVAC lighting on a 99-02 nbs truck.

First, remove the dash bezel to get at the control module.




Remove the two bolts with a 7mm socket, and squeeze in the clips on each side to remove the module. Then gently unplug the two plugs from the back.




Gently pull the knobs off the shafts. Mine were a little tight, so I actually removed the four bolts from the back and pulled the halves apart a little to get the knobs started. You don't have to worry about the position, because the shafts are keyed with a flat spot.




Flip the whole thing open, and remove the two bolts holding the smaller board behind the buttons. Then gently pry the large board out of the backing.



Carefully desolder the bulbs from the boards. If you have a desoldering tool, use it. I don't so I just pressed the hot iron to the pin from behind while pulling on the bulb. Here are the two circuit diagrams.





Two things to note. On the main board, the lights are wired in two pairs of lights in series. I showed the positive side of the circuit for reference. On the small board, in my truck, the last socket (first on the left in the diagram) is not used. Yours may be different. I don't have whatever option that is.

Now you can solder in your resistors to the positive side of each connection. I used 1/2w, 270ohm resistors. You can adjust the value to get the brightness you want. I used chuck16's suggestion. Solder the negative (short lead) side of each LED to the negative side of each connection, then the positive lead to the other side of the reisistor. Then trim off excess lead. Unfortunately, the flash ruined all the pics I had of this part, but basically you just have to be aware of the space requirements, especially on the smaller board behind those buttons, and make sure you don't short anything to any other parts on the board. Like chuck16, I also pointed my LEDs downward to make them fit. You can now carefully plug this in and test it. Once you are satisfied, put it all back together, and hopefully it looks something like this.



The bright spots are not really as noticable in person as in the pics.

[kenwood guy]

[/quote]



The bright spots are not really as noticable in person as in the pics.[/quote]






Great work man !!!! can you also get a parts list up and where I can get my hands on 1/2w, 270ohm resistors??? and the led bulbs near home???? radio shack???? or online somewhere??...and one more thing about the center half moon selector I think I want to keep the red zone for heat but change the rest is that possable???

[guumbah]

Thanks!

I used seven 5mm Ultra Bright Blue LEDs. Unfortunately the packaging does not state the mcd, but I think the store shelf said 3000. I also used seven of the 1/2w 270 ohm resistors. These are a little large, and I think chuck16 used smaller (maybe 1/4 w?) with success. I think if I were doing it again, I'd go with smaller to make the space issues easier. Same with the LEDs behind the buttons. You might want to try 3mm instead for more room. Also, if your truck uses whatever that fourth space is for on the bottom, you'd need one more LED and resistor.

I know you're in SoCal, but where exactly again? Can't remember. I got this stuff at MarVac. They have a few locations around. I went to Costa Mesa. They also have this stuff at Orvac in Fullerton if you're near there. Radio Shack I don't think sells this kind of stuff anymore. At least the one over by South Coast Plaza doesn't seem to. Worst case look up electronics suppliers in the phone book.

On my truck, that red area for heat is opaque, I think. It looks painted on. I suddenly don't remember if it lit up before or not. You'll be able to tell when you take off the front. You could try a white LED in the middle maybe. Or red. Not sure.

The only problem I ran into was that the LEDs' leads did not take the solder as well as the resistors, and when I figured out that I had to reverse two of them, I ended up scorching off the connection on the board on two of them. No big deal to fix with a little jumper wire, though, which is why I showed part of the circuit on the diagram.

Good luck! Let us see how it turns out!

[BlenderWizard]

eBay, man. Go to eBay...

[kenwood guy]

o yea!!

[kenwood guy]

I have a parts list would this be right guys?? (sure would hate to order the wong parts)


Resistor
http://cgi.ebay.com/270ohm-1-2watt-M...QQcmdZViewItem


now you said you think the bulbs where 3000mcd??? can someone please verify this...... and if i can get away with smaller on the buttons

http://cgi.ebay.com/Lot-of-100x-Ultr...QQcmdZViewItem


by the way I live in the sgv part of socal

[guumbah]

Those LEDs look right. Same viewing angle as what I have and everything. I am 90% sure they were 3000mcd marked on the shelf.

Those reisistors - is that price for just one??? I couldn't really tell. If so, that's a ripoff. I paid like $1.50 for a pack of six.

If you're in sgv area, I think there are some electronics supply places in some of those industrial parks up that way. It's been a while since I've been in that area.

[kenwood guy]

Originally Posted by guumbah

Those LEDs look right. Same viewing angle as what I have and everything. I am 90% sure they were 3000mcd marked on the shelf.

Those reisistors - is that price for just one??? I couldn't really tell. If so, that's a ripoff. I paid like $1.50 for a pack of six.

If you're in sgv area, I think there are some electronics supply places in some of those industrial parks up that way. It's been a while since I've been in that area.

yea there are a few industrial parks im going to have to look around im going to go ahead and order the bulbs for now

[TexasF355F1]

That's fucking cool. I'd definately have done that if I still had my truck. But I think I'd choose red/orange.