LEDs wired to cargo lamp switch problem

[K150097]

Hi Guys,
I just installed some LEDs in the bed and wired them via a relais to the Blue/White wire on the cargo lamp switch.

I can turn them on and off, when the interior light is on.
If I leave my truck, the interior light is on, LEDs off.
After 30 seconds interior light shuts off by itself and the LEDs turn on by itself.
So when my Interior lights are off, the LEDs are on and I cant shut them off with the Cargo Lamp switch.

The point I dont get is, why is the Caro Lamp off but my LEDs on. Measured it.: (THe blue/white wire goes from the cargo lamp switch to the cargo lamp if I look in the wiring diagramm.)
Cargo lamp switch off interior light on = 0 Volts at Blue/White wire on cargo switch. LED off Cargo lamp off
Cargo lamp switch on interior light on = 12 Volts at Blue/White wire on cargo switch. LED on Cargo lamp on
Cargo lamp switch off/on interior light off = 12 Volts at Blue/White wire on cargo switch. LED on Cargo lamp off

I want to wire my LEDs via a relais to the cargo lamp switch but it is not possible, when the Blue/white wire has 12V even when the switch is off.
But I saw a Video on Youtube and it worked for him with wiring his LEDs to the Blue/white cable.

So I was wondering if the blue/white wire goes not directly to my cargo lamp. I dont know.

Maybe you can help me with that.
Thanks
Colin

 

[DallasTahoe]

I just today added a couple of lights to run off of my dome lights, when the doors open or if I turn on the interior lights. I didn’t wire them to the switch, or to a relay, but directly to the socket itself. I think the relay may be your problem.


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[DallasTahoe]

if i understand correctly you have wired the leds in parallel to ground with the cargo lamp bulbs (which find their ground path through the white wire ground switching courtesy switch circuit). And the two parallel paths are fed power by the blue/white wire on the cargo lamp switch output? Are the leds wired at all through the white wire ground path for the cargo bulbs?

The blue/white wire should go from the cargo lamp switch directly to the cargo bulbs according to my schematic too.

Well I’ve got a Yukon and my red wire on the led went to the white wire and the black from the led went to the white and red wire, no black colored ground, I’ll take it off and get a pic for you in a lil while. I didn’t wire in parallel, just soldered the wires to whatever wire made them come on. At the same time these aren’t cubes, these are just little flat leds


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[delta_p]

ok i understand now since you wired to the bulb socket.

Also i was not exactly sure how the OP had his relay and leds wired

 

[K150097]

This is my wiring.
Hope you can see how I wired now.

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[delta_p]

From my 96 c1500, When you have the interior light/ dimmer switch set with interior lights off and on the 20 seconds timer, the ground path for all the bulbs including the cargo bulbs are through the lamp control module. The lamp control module is continuously powered through fuse 3.

1) when a door is opened the module is activated. The module gets its operating voltage from fuse 3, same as all the bulbs. The module senses the door jam switch and the module provides a ground path for the circuit consisting of fuse 3 to all the bulbs (including the cargo if you have that switch on) for 20 seconds, then switch off the ground path.

2) If you set the interior light switch to on using the dimmer switch, that provides a direct path to ground for all the bulbs including the cargo's which will light with the cargo switch. the lamp module is not part of this circuit.

So your problem is only during 1) when the ground path is through the lamp module. And your LED's relay control side is in parallel with that path. where it says "from interior lamps" on your schematic that goes to the lamp module under condition 1).

So the only question is, and i'm scratching my head too, with the cargo switch off and after the 20 seconds when the lamp module ground switches ground to off, how is the relay getting voltage/ power to activate. The only possible power source and path is at the lamp module back through the bulb cargo bulb path through your relay and to ground. but i don't see how it could be?

can you measure the voltage at pin 85 with your relay installed, open the door and then close it wait 20 seconds and measure the voltage during all that? A relay will pull in at a voltage less than 12 volts and it doesn't take 12 volts to hold one closed.

Take the cargo bulbs out and see what it does.

 

[K150097]

THANKS!

Oh and wow yes, I took the cargo bulbs out and now the LEDs stays off when the interior light is off.
Thanks!
So if I would solder a diode in the blue/white wire it should work even if the cargo blubs are in, am I right? A 15A Diode should be good or am I missing something?



(Voltage Pin 85:
Cargo Switch off, open door = 0V
Cargo Switch off, cloesed door (less than 20 seconds) = 0V
Cargo Switch off, cloesed door (more than 20 seconds) = 12V

I measured at the caro bulb aswell and as I understand, when interior light is on, you switch the Cargo light with you cargo switch on and with the PLUS path.
When the interior light is off, the cargo light is not connected any more to the ground path but has the Input Voltage off 12V.

So yes, in a way, when the lamp module if off, the blue/white wire gets power from...I don't know.)

 

[DallasTahoe]

THANKS!

Oh and wow yes, I took the cargo bulbs out and now the LEDs stays off when the interior light is off.
Thanks!
So if I would solder a diode in the blue/white wire it should work even if the cargo blubs are in, am I right?



(Voltage Pin 85:
Cargo Switch off, open door = 0V
Cargo Switch off, cloesed door (less than 20 seconds) = 0V
Cargo Switch off, cloesed door (more than 20 seconds) = 12V

I measured at the caro bulb aswell and as I understand, when interior light is on, you switch the Cargo light with you cargo switch on and with the PLUS path.
When the interior light is off, the cargo light is not connected any more to the ground path but has the Input Voltage off 12V.

So yes, in a way, when the lamp module if off, the blue/white wire gets power from...I don't know.)

I don’t know dude, I didn’t use a diode


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[delta_p]

what did it do when you "Cargo Switch off, bulbs out, cloesed door (more than 20 seconds) = ????V


If for some reason the lamp module has found an alternate ground through your relay coil (or to bias the solid state transistor if you have a solid state relay) and it do not really load it down much, but enough current to allow the relay to operate, then you might could try a diode. I'm still confused as to how it getting power.

But the diode would have to be in the blue white wire after your relay connection, and in the part of wire going to the bulbs. And there will be forward voltage drop across that diode, though small, dropping bulb voltage in your normal operation of those bulbs.

 

[DallasTahoe]

what did it do when you "Cargo Switch off, bulbs out, cloesed door (more than 20 seconds) = ????V

Mine acts just like normal, turns off after 20 seconds and everything, like I said I soldered the connection directly to the bulb socket ends. I tested them of course with the light on to make sure I had the polarity correct. I think maybe you were overthinking the process, trying to put the lights on a relay (which is good depending on the lights)


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