# Why is the LED of my Illuminated rocker switch always on?

I recently purchased a rocker power switch from RadioShack (103-R13-135B-02R-EV) and it works great. However, even when the switch is off, the small red LED stays on. Is this normal? Won't this unnecessarily drain my 9V battery?

• There may be some confusion here. The product page on Mouser says that illumination is LED. The catalog page says 103-R13-135B-02R-EV [...] Illum. Green/Neon. The datasheet which you've linked, however, doesn't show the LED (drawing at the bottom-right of the first page). It shows Neon. However, you are saying that the illuminator had lit up from 9V supply. A Neon lamp would not light up at such low voltage. Is it possible that you have the part number (model number) confused? Aug 6, 2014 at 19:39
• In any case, there's another question: how is your switch wired? A diagram wouldn't hurt here. Aug 6, 2014 at 19:42
• I can't post a circuit at the moment, but how exactly do I wire this switch? I could not figure it out from the data sheet, so I simply rearranged my wiring until the switch worked. Regarding the datasheet issue, it is possible I linked the wrong datasheet. My switch has the lettering "R13-135" on it, and a google search returned the link I posted above. Aug 6, 2014 at 19:48
• Aug 6, 2014 at 19:52
• @user43578 "...to be honest, I'm not sure which one I have, as I've thrown out the packaging." facepalm... Back in my days (and I'm not very old) they would send you to dive for it. After pulling the packaging from the jaws of the garbage truck a few times, one learns the value of writing down part numbers, and of having a long-term garbage bin for dry technical packaging. Aug 6, 2014 at 20:00

I believe that this is the internal schematic of your switch:

Based on that, if you want to wire the switch so that the light turns on and off with the switch, you would wire it as follows:

• Pin 1: +Voltage power in
• Pin 2: Switched power for your circuit
• Pin 3: 0 volts

I'm guessing that you have pin 1 and 2 reversed, which would cause the LED to be always on.

And to answer your question, yes, if the LED is on, you are draining your battery. :)

• I will wire this up when I get home, and post back if it doesn't work. Aug 6, 2014 at 20:41
• Except this is a Neon light and not an LED on the schematic. The O.P. seems to be providing a datasheet after datasheet, which show something similar, but there is no evidence that they actually represent the physical part that he has got. On that note, I stop following this wild goose chase of a question. Aug 6, 2014 at 20:56
• @NickAlexeev Yes, the schematic I grabbed has the wrong symbol for the light. However, I believe that RadioShack only sells the LED version of this switch, so I still think my answer is correct. Aug 6, 2014 at 21:14