lighted toggle switch lights part time

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Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=112804
Printed Date: July 26, 2025 at 11:07 PM

Topic: lighted toggle switch lights part time

Posted By: scheetz83
Subject: lighted toggle switch lights part time
Date Posted: March 31, 2009 at 12:56 AM

Hi guys First off sorry if this is in the wrong area of the forum.

I have a 2005 mustang and i created a switch panel between the center vents consisting of 4 Lighted LED toggle switches. The switches are made by pilot and the toggle portion of the switch is billet aluminum with a blue led at the tip.

The first 2 switches run 2 sets of fog lights. Switch 3 is a KITT scanner and 4 is a spare. My issue is, once i got the fog lights hooked up to the switches the LED on both the switches has now started working intermittently. I cant imagine both Switched being bad. It is odd because the LED may come on and work fine but if you turn it off then back on it wont come on. After turning the switch on and off several times it may or may not come back on. Some time there is a delay for the light to come on say 1-2 secound. Thought all this the switches are working IE turning on the Fog lights, I just want the LEDs to work also :-(

Power and ground for all 4 switches are picked up at the same spots and both sets of fog lights are setup to use relays

any help would be great thanks guys
Michael

Replies:

Posted By: i am an idiot
Date Posted: March 31, 2009 at 5:57 AM

On those lighted switches, the sole purpose of the ground wire is to ground the LEDs. If the switches are switching the lights properly, I would check the ground. If the ground is in tact, you have bad switches.

Posted By: KPierson
Date Posted: March 31, 2009 at 7:57 AM

Did you put diodes across the coils of each relay? If not, the relay coils could be damaging the LEDs.

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Kevin Pierson

Posted By: scheetz83
Date Posted: March 31, 2009 at 9:55 AM

I have checked the ground and it is good and solid.

KPierson wrote:

Did you put diodes across the coils of each relay? If not, the relay coils could be damaging the LEDs.

That went over my head just a tad. The one set of fog lights came with a wiring harness and the relay was part of it. The other set is using just a bosh 40amp relay. I know a diode limits current to flow in 1 direction but what 2 poles do i need to jump. Could this cause the led to work intermeitnetly. I would think that if the led got hit with more then it could handle it would stop working completly

Thanks for the help guys

Posted By: KPierson
Date Posted: March 31, 2009 at 10:30 AM

I wouldn't think it would cause intermittent issues, I would think it would cause total failure. Resistive components (like incandescent bulbs) don't need protection but solid state devices (like LEDs and transistors) do need protection.

The diode would go from Pin 85 to Pin 86 with the striped side facing the 12+ pin and the non striped side connected to the (-) side of the coil.

The only other thing I would think to do is to measure the voltage from the 12vdc pin of the switch to the ground pin of the switch when the LEDs aren't working - if you ca verify voltage is present when the LEDs arn't working then you know the switch is the problem. However, I would think it would be near impossible to have identical itermittent issues between the switches and would expect more that there is a wiring issue somewhere.

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Kevin Pierson

Posted By: ckeeler
Date Posted: March 31, 2009 at 7:14 PM

if the "load" side of the switch (what you are powering with the switch) comes on ALL the time and is on when the switch is on even if the LED is not, then you have a bad switch.