PWM and multi-color LEDs for auto

[LED newbie]

Problem w/PWM and multi-color LEDs on vehicle

Any PWM/LED savvy tech:

I am attempting to use a 12VDC LED PWM to drive (4) 3-light [2-red, 2-amber] and (2) 16-light 1-red, 1-amber] LEDs from my vehicle's existing, non-LED, non-PWM, parking light circuit.

At first, I had success using a PWM to dim the LEDs to, at, or below OEM parking lamp intensity with no problems; however, after a few weeks of use the PWM started to act as if there was no GROUND connection and the LEDs returned to full intensity with the PWM having no affect, on or off.

My vehicle parking lights operate on a standard 12VDC, 20AMP fused, ~2AMP max.
circuit. I have checked all connections and ran straight jumpers to battery (pos. and neg.), with no solution (i.e., same result).

When I switch entire circuit, including existing PWM to a stand-alone 18V DC NiCd-battery, all seem to function correctly.

So my question: Has anyone experienced this or does it seem I am using the
PWM correctly?

Thanks,
The Newbie

 

[LED newbie]

Ok,

After finding time to perform a few more troubleshooting options...I noticed that two of the LEDs on the amber 16-light, light bar are out...I haven't had a chance to isolate this light from the circuit (waiting for the weather to warm and more daylight), but am very much hoping this is where my problem resides...anyone have any thoughts/ideas on this?

Thanks.

 

[audioguru]

There is nothing we can do to help you except wait for you to attach your schematic with parts numbers.

Please explain this mumbo-jumbo: "(4) 3-light [2-red, 2-amber] and (2) 16-light 1-red, 1-amber]".
Are you using PWM on the original incandescent light bulbs plus the LEDs? Then what is the light bulb number so we can look up its peak current rating? An incandescent light bulb draws 10 times its operating current when it is turned on until its filament reaches 2500 degrees C.
We also need to find the datasheet for the LEDs that burned out.