Looking for a schematic for the momentary led push button switch.

**OldSpark** · 04-04-2011, 05:34 PM

It sounds like a resistive dimmer, and that you need to connect transfer the LED connections - ie, instead of +ve to +12V and -ve to dimmer, +ve to dimmer & -ve to GND (or vice versa).

(Not that resistive dimmers work well for LEDs, but with bulbs this is effectively a "voltage" dimmer.)
(And on 2nd thoughts, it should be the same for modern (PWM) dimmers....)

**OldSpark** · 10-10-2011, 09:12 PM

FYI - PWM dimmers seem common in modern Jap vehicles.
I pulled a couple from 1995 & 1996 Hyundai Excels. They use a 10A switching MOSFET and appear to be PWM because there is negligible heat when dimming a 50W halogen bulb, and a parallel 12V LED dims in proportion.

I might find out how to reduce it lower dimming limit but otherwise probably won't bother deciphering the circuit - I think it's easier transplanting my old 555 circuit which uses ~10 fewer components, but the same 10k pot and FET switching.

It has a +12V & GND connection with the output being GND PWM dimming (ie, LEDs & lights to +12V and grounded through the dimmer's 3rd terminal).

I have little doubt similar circuits feature in other Jap vehicles...

**soundman98** · 10-10-2011, 09:23 PM

^ those have become a quiet led hobbyist trick-- to pull the oem pwm units from import cars...

**OldSpark** · 10-10-2011, 09:59 PM

Phew! Good to see!
I've had no need - I've had my old circuit etc. (It's now 4 years since I disassembled my 12V camping fluoro to insert my dimmer that was scheduled for ~6 years ago!)
And IMO it's kind of surprising considering the... er, "debate" I had a few years back with an "experienced expert" installer etc on here... (At least this "reality" was only 10 years ahead of my debatees unlike fresh graduates that have been 20 years behind!)

But it was only whilst accompanying a mate to a wreckers that I happened to notice... and thought...
Oh dear - I forgot to find out their price....

But as a convenient matchbox-sized ready built PWM dimmer - and I suspect easily upgradable to 100A...
I might just reassemble my flouros. Make series plug-in dimmer instead... (Yeah, why get up to dim a light when the dimmer cam be beside you. Geez I'm so stupid....!)

And I like the "quiet led hobbyist trick". Oh poo - should I delete all now?
But yeah, there are those that know and watch the others....

For me it confirms the brilliance (pun intended) that I know some have. And I skip any dim-wit.

**Project07MACry** · 10-14-2011, 10:59 PM

Hallelujah! I thought I was the only one going through this!
I too was able to get the buttons to permanently light. However, is anyone familiar with getting them to light when the device (i.e. Mac Mini) is on? Any input is greatly appreciated!!