Show me your LED's!

[MOBS]

This is just for the people with the "tethered light sockets" on their HVAC assembly.

The hvac lighting circuit is a resisted circuit(notice stock hvac bulbs are dimmer than cluster), the hvac bulbs run at a lower voltage so they give out a dimmer/softer light. Since LEDs do NOT dim, they will pull more amps at lower voltage to stay lit. This circuit can NOT handle the excessive amp draw and will burn the physical copper leaf path in the circuit board. This resisted path MUST be bypassed in order to use LEDs in the hvac. The headlight switch bulb is similar except to dim it, they just used a tinted cover on the bulb itself.

I will eventually post a thread on how to fix this. It's actually very simple.



This is the "tethered hvac assembly", notice the light sockets are all wired in parallel to each other:

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This is the rarer style that's more compact, and was probably GM's fix to the crappy built ones you see most often. This style does NOT require the above mentioned fix to run LEDs:

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[TruckinAin4Sissies]

You're right Mobs! Before there were replacement bulbs available we had to do it old school.
Find voltage and throw a resistor in a single LED.

 

[MOBS]

Yeah, that's what I do to drop voltage from 12v down to 5v. But the problem comes into play when the circuit has it's own resistor that cuts voltage in half, then gets cut even more as it enters the LED itself....lowering voltage requires increasing amperage, if the circuit can only handle normal amperage and the 4x LEDs try to retrieve more to "startup", it will overheat the circuit and cause a burnt path in the board.

If anyone has ran a large sound system on a stock alternator charging wire....or if their alt-charge wire is frayed....then you'll see the wire begin to break down, and it will usually glow a nice orange color. The good thing about it glowing, is it saves you on zippo fluid.

 

[TruckinAin4Sissies]

What do you think about using the current voltage supplied as a trigger for some Leds?

 

[MOBS]

I would think it fine, relays only look for voltage, doesn't take much amperage atall to power the coil and switch the relay's secondary circuit on. Now finding a relay that will support the lower voltage to it's primary side while allowing 12v or w/e to the secondary may be interesting.

But when it comes to the aforementioned hvac assemblies, it wouldn't be worth the trouble of running any extra circuits, bypassing the circuit literally means cutting the power wire on side-A of circuit board and fusing it to the positive wire on side-B of circuit board.

 

[TruckinAin4Sissies]

I know I have a PWM somewhere around here damn it. I'll be in the dungeon methin'-out for a while 'til I get it figured out.

 

[MOBS]

Hahahaha........I like your avatar pic, are those clear tails?

 

[TruckinAin4Sissies]

Nope, not yet

 

[sewlow]

I know I have a PWM somewhere around here damn it. I'll be in the dungeon methin'-out for a while 'til I get it figured out.

When you get out into the light, what do you wear to hide the neck bolts?

"and it will usually glow a nice orange color. The good thing about it glowing, is it saves you on zippo fluid."

And all this time I thought that was a underhood light!



This why I'm just leaving mine alone. Kudos to you guys for having the patience to do this stuff. It would be an exercise in frustration on my part. Excellent info!

 

[TruckinAin4Sissies]

^ You my friend, are talented in the fine arts of Upholstery. I am a novice at electronics BUT am learning everyday