Hi guys,

Working on wiring a 2018 Nissan Rogue usb port with radio to my car. Tried the ILL+ and ILL- wires, the port briefly lit up then stopped lighting up. Used a 9V battery for testing, figuring its a 12V device. I was reading through the service manual (of a 2015 cuz it seems the site is down) and it looks like the ILL wire from pin 43 on the cluster is a 12V PWM signal? Can anyone confirm this? Not sure what is going on, especially since the service manual says at minimum brightness is maximum pulse width, and full brightness is 0V. It's not a ground switched item AND its an LED.

I double checked my wiring, and it does a diode check at 0.7V/2.8kOhm, which I don't think is right. Well, it did that before I plugged it in too, so maybe not. Wonder if it requires 12V from the power in, and it has a capacitor charged in there?

Anyway:

1) Is the cluster dimmed illumination signal a 12V or 5V signal?

2) Is it high-side PWM switched like I think?

3) What happened with my USB port illumination? Is it fried?

Hi guys,

My pedantic 2am findings are as follows:

1) port is NOT fried

2) ILL- is tied to ground

3) ILL+ is a transistor gate, not the LED main power

4) LED power is provided by 12V supply

5) 12V supply on USB port has 15uF capacitor which caused flash when ILL+ is powered

6) ILL+ is 12V PWM as I suspected.

You're correct that the circuit has a high side PWM coming from the instrument cluster, but the circuit is shown as being direct drive and not gated. However, what's in the FSM is a little wonky. It shows a 12V PWM at 400 Hz which is normal enough, but it also shows the PWM at 90% duty for minimum illumination and 0% for maximum. That can't be right because there aren't enough wires on most of the LED connections to be using P-channel gates and not direct drive. So I think the parameters shown must be a block-copy error from older clusters using a low-side drive. You can confirm that by measuring what comes out of pin 43 at various brightness levels. The WD indicates it should go near 12V at maximum and near-or-at 0V for minimum, where the FSM indicates the opposite. If the FSM is right then something is majorly twacked in the wiring documentation, so I expect you'll find the WD is correct and the FSM is in error.

That said, why anything would blow up when you connect 12V to illumination+ and ground to illumination- on the '18 USB port, I have no idea. The WD shows it being a straight-through connection from anode to cathode on an LED (of course with an internal ballast resistance unshown in the WD). So putting power across it should simply light it up.

VStar650CL wrote: ↑

Sun Dec 17, 2023 8:55 am

That said, why anything would blow up when you connect 12V to illumination+ and ground to illumination- on the '18 USB port, I have no idea. The WD shows it being a straight-through connection from anode to cathode on an LED (of course with an internal ballast resistance unshown in the WD). So putting power across it should simply light it up.

FSM is wrong here, its a switched driver using a BJT. 12V is required for it to light up. Put it in my car, hooked it up to the ILL+ control signal....we're in business

That must be unique to the aux port, most of the other illumination only has 2 wires and can't possibly be transistorized. But the WD's rarely show any internal circuitry, so I'm not surprised either. Sounds like you're sure it's a high side drive, so I'll inform TechLine of the error in the pin descriptions. I hate when they make stupid block-copy errors like that, especially on a circuit you could potentially blow up by grounding the driver.