LED stop lights

[BauDemo]

I ordered these:
http://www.dealextreme.com/details.dx/sku.48174

I was hoping to use them as a replacement for the Think stop lights.
I tested them with my LAB power and they seem to be working fine - the minus on the cylindrical part, and the plus on any (or both) of the bottom terminals and the lights work.
When I put them in the Think, and I press the brake the light work, but when I turn the headlights on I get only smoke coming out of the LED lights. I looked at the electrical wiring diagram, but I am not sure I am making any sense of it.
I seem to recall someone talking about changed polarity, and I tested the LED lights with reversed polarity and they did not work, but no smoke was emited either.

Anybody got any ideas?

[hens]

Did you use the 2-pole type of bulb?
If you put a single-pole bulb in a 2 pole socket, you got problems.

The 2-pole bulb has a common ground in the socket, and 2 poles in the bottom.
If you insert a single pole bulb it will probably short between the poles and return the current through the ignition system when the brake pedal are used.

[BauDemo]

you probably did not see the photos in the link... so I am pushing them here...
two poles... and tested with 12v dc lab supply... but smoke in the car...

[hens]

Check the polarity in the lamp, socket = negative and poles positive.
If it is correct, you have got a pair of defective lamps.  Return to supplier.

12 volt diode lamps work usually as diodes, if wrong polarity they doesn't light up.
Some have an internal rectifier, and work in both direction

[BauDemo]

I tested them with my LAB power and they seem to be working fine - the minus on the cylindrical part, and the plus on any (or both) of the bottom terminals and the lights work.

As I wrote in my first post I already tested them and they work fine when supplied by the lab power supply.

[cra]

It might be obvious, but did you check the socket on the Think for correct voltage and polarity? I am also thinking perhaps the end-dots and side-dots on the LED bulb might be 90 degrees offset to the original bulb, so the two end-dots effectively short out the socket in the car?

[El rayo]

What voltage on the lab power supply did you use to test the LEDs? Are you sure that you've got 12 volt LEDs; I've seen 6 volt ones advertised.

I'm successfully using "1157-RLX3" from superbrightleds.com

[BauDemo]

Mistery solved.
when I apply 12V between the two pins on the bottom of the LED bulb, the bulb consumes 0.5A... I did not wait for the smoke this time, but that explains a lot.
Most of the time brake light pin in the car is usually at ground when the other one (the one that is always on) is at 12V... this, combined with a defective or poorly designed light = smoke.

Thanks to everyone for the suggestions!
I will keep you posted on the outcome.

[cra]

File a defect report with customer service. In my eperience they send a new item if the one you got is faulty. Happened to me a couple of times. Anyway the stuff I order there is so cheap that it doesn't matter if it's sometimes defective/damaged during transport.


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