S100 Aux 8 shift light output

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John Loudon
Posts: 29
Joined: Mon Jul 20, 2020 3:47 am
ECU Model: S100 Pro

S100 Aux 8 shift light output

Post by John Loudon »

Hi

Is it normal for the Aux 8 shift light output to output approx 2 volts when not functioning? I ask as my shift light LED glows dimly when not active as a result but glows fully bright at 12v when the shift light should be active as expected. I was expecting 0v when not active hence why I am asking.

Thanks

John
stevieturbo
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Re: S100 Aux 8 shift light output

Post by stevieturbo »

Pretty sure mine did glow a little too, and others have reported the same.

Although with a regular bulb it is barely noticeable. I'd say if you had an LED type...it might be quite noticeable.
John Loudon
Posts: 29
Joined: Mon Jul 20, 2020 3:47 am
ECU Model: S100 Pro

Re: S100 Aux 8 shift light output

Post by John Loudon »

Thanks. Yes it's an LED. Is there a way to overcome it? Firmware update maybe or someway to suppress it in the software?
Rob Stevens
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Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: S100 Aux 8 shift light output

Post by Rob Stevens »

Try using a resistor to pull the output up to 12v ,500 ohm?
aleksanderk
Posts: 68
Joined: Fri Feb 01, 2019 4:36 pm
ECU Model: S80 Pro
Firmware Version: 6500

Re: S100 Aux 8 shift light output

Post by aleksanderk »

If you use a pull up resistor in this case, could you simply connect the resistor between the anode and cathode (+ and -) on the LED, and the problem is solved?
Or have I misunderstood the concept of this? You don't want the ground in the S100 to "float", so you give it a positive, until the S100 definetly pulls it to ground?
Rob Stevens
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ECU Model: S100 Pro
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Re: S100 Aux 8 shift light output

Post by Rob Stevens »

Yes, that's the same thing.
John Loudon
Posts: 29
Joined: Mon Jul 20, 2020 3:47 am
ECU Model: S100 Pro

Re: S100 Aux 8 shift light output

Post by John Loudon »

But I get 12v when needed. The problem is I get 2v when I want 0v. I want it to give either 0v or 12v depending on whether the shift light should be on or not
Rob Stevens
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Joined: Thu Jul 28, 2011 4:10 am
ECU Model: S100 Pro
Distributor: None-Coil On Plug :)

Re: S100 Aux 8 shift light output

Post by Rob Stevens »

I don't understand what you are saying! The output is only ground (0v) or floating, it does not give out 12v, the 2v you are seeing is coming from the 12v. So just to recap you are using the output 8 purely as a shift light with an LED to 12v and the led is glowing dimly when the output is off. The output is clearly leaking a little ground, try putting a resistor across the LED to shunt the leak away from the LED.

To reiterate the outputs do only output grounds, the only exception is output Aux 5 which does output 12v

I recall on my old P8 the turbo control (I was using this as an additional shift light) flashed my LED dimly when undesirable so I know there can be issues.
John Loudon
Posts: 29
Joined: Mon Jul 20, 2020 3:47 am
ECU Model: S100 Pro

Re: S100 Aux 8 shift light output

Post by John Loudon »

Yes that's the situation Rob. The shift light glows dimly all the time. I am seeing 2v when the output should be inactive. I will have a dabble with whatever resistors I can find in my assorted bits but I would prefer to not have to.

Update - found a 220R resistor which seems to sort it

Thanks for the suggestions
stevieturbo
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Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: S100 Aux 8 shift light output

Post by stevieturbo »

In general, when the output is OFF....it will actually be around 12v.

So the device has 12v on both sides, give or take. It then pulls to ground for an ON state.

It's just how ecu's and transistors work....very rarely do they go actual open circuit for an OFF state like a mechanical switch or relay would do.
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