hello I have installed a custom switch panel on my work truck. I'm using self illuminated led toggle switches. only 1 out of my 5 switches are lighting up. I have ran one power wire to the switch panel and jumped it to every switch. I have also run one ground wire and jump it to every switch. my first thought was a bad ground. but it is the switch in the middle of the switch panel that is lighting up. so if the switch in the middle is properly grounded they all must be properly grounded. the switches are still working properly as in turning the accessory on and off. at first it was only one and I thought it was a bad switch so I replaced it. and it worked just fine for a couple flicks on and off and then that light went out again. also a different one sometimes works and sometimes it doesn't. any help would be greatly appreciated thank you
Assuming your wiring is correct, ensure your inter-LED wiring is of adequate gauge tho assuming 20mA or even 50mA LEDs it's probably difficult to be too thin... IE - ensure GND can handle the combined current of all.
If you change which end or LED the GND attaches to, do the lit LED(s) change? If so it's a resistance issue...
If the LEDs (with resistors) share an external resistance OR are subject to different path resistances then inconsistent lighting can occur, eg typically the same LED or LEDs will light up or NOT light up. That's due the the Zener diode nature of LEDs whereby the one with the lowest Zener voltage may absorb/take available current from others.
However that should only occur when the applied voltage (eg +12V) isn't much higher than LED operational voltage (eg, ~2V for a single red; 3.4V for white or 10.2V for 3 series whites etc).
That's where any external or shared resistance comes into play...
oldspark wrote:
Assuming your wiring is correct, ensure your inter-LED wiring is of adequate gauge tho assuming 20mA or even 50mA LEDs it's probably difficult to be too thin... IE - ensure GND can handle the combined current of all.
If you change which end or LED the GND attaches to, do the lit LED(s) change? If so it's a resistance issue...
If the LEDs (with resistors) share an external resistance OR are subject to different path resistances then inconsistent lighting can occur, eg typically the same LED or LEDs will light up or NOT light up. That's due the the Zener diode nature of LEDs whereby the one with the lowest Zener voltage may absorb/take available current from others.
However that should only occur when the applied voltage (eg +12V) isn't much higher than LED operational voltage (eg, ~2V for a single red; 3.4V for white or 10.2V for 3 series whites etc).
That's where any external or shared resistance comes into play...
okay I think I understand lol thank you very much. so you're saying I should pull the grounds off and put them on different switches and see if a different switch lights up? so should I try to put the ground in a different spot?
No... but yes to your last part.
I interpreted your "
...run one ground wire and jump it to every switch" to mean
daisy chaining one switch to the next with a single takeoff to GND. If each
jump from one switch to the next does have an impact then changing the takeoff point should change which light or not.
In practice it shouldn't since although all wires have resistance, the interlink resistance should be negligible. (Then again, link to solder to link etc resistance could add resistance, and dry solder joints certainly add resistance.)
But I'm considering the fact that you seem to be describing the behavior I described so I'm coming up with possibilities.
The same could apply to the +ve switch side tho since they are all separate connections that is unlikely (tho they may share a common
resistive +V supply). However if LED(s) extinguish when another is switched on there could be an issue tho again IMO that is more likely to be a GND issue.
A simpler test is to add a parallel connection to the switch/LED GNDs - eg, alligator-clipped test leads, paper clips, wire, etc to short between LED GNDs and GND - and see if anything changes.
Usually things like this are wiring problems but without any circuit or switch data to go off, and assuming you have already checked wiring and perhaps that each switch has +12V (to its LED), I'm offering the info I provided.
I'll add that some switch data is IMO difficult to follow. For example I found specs relevant to the switches used in
New guy, wiring an LED light bar tricky to ascertain and even then IMO they were ambiguous (ie, tho I could apply my common experience I could not establish the
switch physicals and hence circuit complications) and I wasn't prepared to drill further.
Circuits like that should be checked for wiring correctness and then operational correctness - ie, the switches are switching and they switch full voltage irrespective of how many are switched/connected. IE - as they say, TEST!