Confusion on illuminated switch

[Silver Serpent]

So I picked up the blue ring illuminated AV switch for my newest saber - http://www.thecustomsabershop.com/DP...itch-P433.aspx

I was getting ready to start wiring work, when I noticed none of the pins were labeled. Trial and error would be good enough to figure out the switching portion, but I didn't want to hook up the LED backwards. I pull out my trusty multimeter to check the resistance and polarity of the LED, and I get really confused.

The LED illuminates in both directions.

I'm not really an electronics guru, but I'm pretty sure that LEDs are supposed to only work in one direction. I got no change in resistance in either direction on the LED, no matter which lead I used as negative or positive. So, what is going on?

/me scratches head

Edit: I've got the "negative" marked according to the diagram shown in the store, assuming it's the closest to the 2 commons. Still don't know why it lights up backwards.

[iamdrake]

I have gotten 2 of these type of switches, if you look REALLY close under the glue there is a raised positive and negative symbol.

[Silver Serpent]

Any markings on the switch itself are hidden under some kind of plastic seal material. I couldn't see markings of any type. Here's what I have found out though:



Positive LED terminal is closest to the NC terminals. Negative LED terminal is closest to the C terminals. A little testing with my multimeter and I determined the position of the terminals.

I go to check the resistance on the LED, touch my negative lead to the negative terminal, touch my positive lead to the positive terminal, and the LED illuminates. Perfectly normal behavior, except the multimeter doesn't read ANY change in resistance.

I touch the positive lead to the NEGATIVE terminal, and the negative lead to the POSITIVE terminal, and I get identical results. The LED illuminates and resistance doesn't change.

The only thought that came to me last night was that my multimeter was wired wrong and sending an AC current to the LED, causing it to light on every other cycle, while still showing max resistance. (It's a cheap Walmart multimeter) Gonna borrow my dad's Fluke and see if I get more useful results. If not, I'm gonna assume I have a magic reversable LED and keep on working.

[RevengeoftheSeth]

Is it possible that your multimeter has reverse polarity protection?