LED ECU reader ('89 200 t FWD)

[Tom Christiansen]

Hi,

>I need to get a LED w/resistor to read the codes of my ECU. Radio Shack does
>not specify which, if any, of their LEds have a built-in resistor. If anyone
>can tell me the reference number of a working LED, I'd be a lot grateful.

I'm assuming that the ECU gives a 12V signal out...

Buy a standard red LED. The LED will have two leads, one being about 1/8
inch shorter than the other. On most LEDs the case/housing of the LED will
also have a flat face by the short lead indicating the cathode (minus).

Solder the long lead of the LED to a resistor with resistance between 560
ohm and 1000 ohm (1k ohm). The other lead on the resistor is the plus
connection of your tester, the short lead on the LED is the minus
connection. You can solder some wires on to these connections if you so desire.

If the LED doesn't light up when you apply 12V to it, then reverse the
connections.


Tom