LED car lights - repair

Thanks. My meter shows an infinite resistance one way and 17 M ohms the other. My IDM 99 II meter does not have a specific diode function, though it appears the IDM 99 III does.

Dead CFL ligtbulbs are a good source of diodes and other components.

You can't test a diode on a digital multimeter on the normal resistance ranges, like you can on an old moving coil meter.

Use the current (mA range, a 9v battery and current limiting resistor say 10K ohm and diode under test, all in series.

It might not be using a high enough voltage to forward bias the diode, so this by itself doesn't indicate a fault. Measuring the voltage drop across the diode when the light is on would be more useful (should be somewhere between 0.5V and 1V).

If you rig up a battery and bulb - taking less than 1 amp - and insert the diode in series with them, the bulb should light with the diode connected one way, but not the other. However, if it's easy to remove just fit a new one - they're only pennies. And ask for a decent DVM for Xmas. ;-)

How you open them up?

Rotary tool, Dremel style, and an abrasive disk might be the best way.

I thought of that ;-) but was wondering if there might be a "secret handshake" that pops them open neatly.