What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Illuminated switches.. I don't understand!

Help!

I have some DPST rocker switches with dual LEDs. 8 pins per switch. Eventually figured out that the top 2 pins provide power and earth to the upper LED, and the bottom two pins go to the lower LED that illuminates when the central pins are closed, connecting the lead into and out of the switch.

Ive tested these with a power supply across the switch, and they work as desired. I then asked someone if the same switch would be ok for the battery contactor, that is switched to ground.
I assumed it would be fine... electrons can't know at what point they are in between the battery +ve and battery negative, so why would it matter if the switch was on the negative side of the 'device' or the positive side... but the guys I purchased the switch from said it wouldn't work as the lead into the switch isn't a red positive, so it cant be 'jumped' to the positive side of the LED. I just don't get it... an I being dim?? If I am, how do I get the illuminated switch to work when the battery master switch is turned on?
 
Couple places to check

Hi,
if you search through the rockerswitchpros.com website, they give some instructions on how to wire up switches so they'll illuminate. Also in the vertical power instructions for the VP-X there's methods for connecting illuminated rocker switches.
 
It would help if you posted a link to the switch datasheet. Without more info, all I can suggest is to run a separate positive wire to power the LEDs. Are the LEDs designed to be powered by 12 volts? In other words, do the LEDs have a built in series resistor?
 
Looked up the data sheet for Part# 11-03161 on aircraft spruce. The coils can handle 9 watts continuous. As long as you keep the total current through the switch below that you'll be fine. The switch data sheet says typical current for the LED is 20ma, or 0.25 watts. So max draw if you're powering both lights will be 0.5 watts in the switch. You'll be fine to put it upstream or downstream of the contactor with no issues. The data sheet doesn't give a current value for the incandescent bulbs. If you're not going LED just verify with rocker switch pros that the total lamp power draw will be less than 9 watts.
 
Last edited:
Yes you can

You can absolutely wire them up to drive either +12 or Ground. I have many wired both ways. You can also wire them to light up when closed or open.

Think of it this way:
1) The LED needs +12 and Ground to light up. If you disconnect either leg, the light goes off.

2a) If you are switching a ground wire, then connect the LED positive to +12, and the ground leg to the switched leg. Now it will only light when the switch is closed.

2b) If you are switching a +12 load, then connect the LED ground to ground, and +12 leg to the switched leg. Then It only lights when closed.

3) If you want the LED on when the contact is open (for instance to act as a warning that the switch is off, just wire the appropriate side of the LED to the "normally open" leg of the switch, so that the LED circuit is closed when the switch is in the open position.

For all of the above, make sure that the LED is never driven from the +12 side of the battery, and only driven from the +12 side when the contactor is engaged. Because even an LED will drain your main battery.
 
Back
Top