Why does my LED toggle switch not illuminate?

[Rick Lee]

This is the switch.



The three spade connections are power, accessory and ground. This is for the foglights on my bike. Switch works fine, but the LED does not illuminate. I bought it at Radio Shack yesterday because it looked identical to the switch I already had on there, which I thought was non-illuminated. But both switches are identical. I want a green LED, since I can't otherwise see if the foglights are on in the daytime while sitting on and parking the bike. I find it hard to believe I got two switches in a row with bad LED's in them. But the wiring is so simple, I can't see how I can screw it up. How do I get the LED to go on?

[krystar]

u sure u got the positive and negative right? LED's are diodes. only hook em up in one direction

[Rick Lee]

With power, accessory and ground, how can you get it wrong? That said, I've tried every combination just for the hell of it. No LED.

[Rick Lee]

FWIW, I wasn't running a ground on that switch. Seemed to work fine without one and the draw is so low. But I tried it with an alligator clip lead, grounding it to the frame - nothing. Does it need to go to the neg. battery terminal?

[911pcars]

Originally Posted by Rick Lee

FWIW, I wasn't running a ground on that switch. Seemed to work fine without one and the draw is so low. But I tried it with an alligator clip lead, grounding it to the frame - nothing. Does it need to go to the neg. battery terminal?

The label confirms. It says (in order), Power, Acc and Ground.

Yes, the ground terminal on the switch must be grounded for the light to illuminate (ON position).



My retail source doesn't specify if it's an LED. Here's a drawing with the internal electrical circuit:
http://www.delcity.net/images/linedrawings/73179.pdf

Sherwood

[Rick Lee]

I had been running it for a while without grounding it and it worked fine, though still no LED. When I grounded it to the frame, the LED did not illuminate. Do I need to run it to the neg. battery terminal?

[911pcars]

Originally Posted by Rick Lee

I had been running it for a while without grounding it and it worked fine, though still no LED. When I grounded it to the frame, the LED did not illuminate. Do I need to run it to the neg. battery terminal?

Rick,
Like any electrical load, you should be able to connect to any grounded, metal surface in the car. Do you have a multimeter? Connect one test lead to the source wire, then use the other test lead to probe your potential ground connection. If the ground is good (e.g. not insulated, not a continuous path to ground, etc.), it should read the same as battery voltage. Not being a motorcycle guy, perhaps there are subsections of the bike that aren't electrically grounded.

There's also the possibility the switch is kaput as new.

Hope this helps,
Sherwood

[Rick Lee]

It sounds like I bought two bad switches in a row, one from Fry's and the second from Radio Shack. What are those odds? I've used an alligator clip lead to run that ground to several areas that have fine for other grounds. No LED.

[rick-l]

I have to laugh at the review on Radio shack "don't buy this POS it doesn't even come with a wiring diagram".

The diagram referenced does not tell you the voltage of the LED or what way current is supposed to go through it.

[Rick Lee]

I can't remember, but I think it's rated for 20a and 12v. I have a 5a inline fuse running and my foglights are LED and only draw 3a. I have to think the LED is rated well within the switch's capabilities.

[911pcars]

Originally Posted by Rick Lee

I can't remember, but I think it's rated for 20a and 12v. I have a 5a inline fuse running and my foglights are LED and only draw 3a. I have to think the LED is rated well within the switch's capabilities.

IF there's an LED inside, it will have a resistor in the circuit to handle 12VDC. In addition, the lamp is in a branch circuit, thus the lamp isn't affected by accessory load current. The contacts in the switch pictured are rated 20A @ 12V.

Sherwood

[idontknow]

are the foglights switched on the neg side?

[911pcars]

Originally Posted by idontknow

are the foglights switched on the neg side?

Nice catch. Some Japanese import cars position switches on the ground side of a load. If this is the case, the bulb in the switch won't work.

Sherwood

[Rick Lee]

Not sure what you mean here. I think I've tried every combination of connections and the foglights work just fine. I just can't get the LED to work. What else can I do?

[911pcars]

Originally Posted by Rick Lee

Not sure what you mean here. I think I've tried every combination of connections and the foglights work just fine. I just can't get the LED to work. What else can I do?

1. Switch on the source side of the load (typical):
battery > fuse > switch > load > ground

2. Switch on the ground side of the load:
battery > fuse > load > switch > ground

An illuminated switch can only work when it's located on circuit type no. 1 above.

3. Here's the same circuit as no. 2, but with an illuminated switch.
battery > fuse > load > switch > ground
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiV
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiibulb > ground

If your fog lights are wired like no. 3 above, the bulb in the switch won't work. Reason, the bulb creates a series-parallel path with the load (sorry, maybe getting too technical), but the load (e.g. fog lights) would use up all of the 12V.

Sherwood

[Rick Lee]

Success. I don't know exactly how this worked, but I ran a wire from the ground spade on the switch to the ground wires from the foglights, joined them all at the nut and bolt on the frame and the LED lit up.

Next problem is how to mount the damn switch. I had used some 3M Dual Lock to mount it to my instrument cluster. But once it got hot outside, that glue was basically oil. Then I tried some of that double-sided foam tape. Ditto. It's so damn hot here, no glue works. I don't want to drill or cut into the plastic on the bike anywhere. I wonder if Krazy Glue works in the hot climate.

[RWebb]

hose clamp?

[Rick Lee]

A hose clamp might be a little too harsh for those wires. But the main catch is that the switch, which has all flat, smooth sides, needs to be snug and secured to something, so it doesn't move when I flip the toggle up or down.

[911pcars]

Originally Posted by Rick Lee

Success. I don't know exactly how this worked, but I ran a wire from the ground spade on the switch to the ground wires from the foglights, joined them all at the nut and bolt on the frame and the LED lit up...........

Uh. Ground wire on fog lights not grounded. Can't assume too much.

Sherwood

[Mr.Puff]

Zip-tie?