Auxiliary Outputs...Gear Shift Light LED question

[Nevalite]

Hello,

I have a Motec M400 ECU and I am trying to setup a gear shift light (single LED) on my dash. What I did was wire the anode of the LED to a 550 ohm resistor and in turn to a 12V source (A26 on the ECU). I then connected the cathode of the LED to Auxiliary output 6 on the ECU. At first the gear shift light worked perfectly but as soon as we went out for the first day of testing it stopped working. It did however work at one point during the test session, random.

I have a question about how the auxiliary outputs function. From my understanding they give a positive 12V signal constantly and then when they become active they switch to ground. (If that is how you set it up in the software).

I did some measuring around and it would seem that AUX outputs 5,6,7,8 read 3.39V unactive and 0V active, this seems weird...I was expecting 12V and 0V?

I also noticed that even when an aux output is not set to any function, it reads 3.39V.

AUX outputs 1-3 seems to be reading 12V and then 0V. I did not measure them but in the software you can see these voltages.

Auxiliary output 4 does not seem to work at all, it reads 0V regardless what I do to it.


Anyone have any ideas what is going on here? Should I try giving the shift LED constant 5V instead of 12V? Are all the other outputs acting normally?

Thanks

[Scott@FP]

Might just be burning the LED's up like I did. Find out what the current limit for the LED is, use the appropriate resistor value for max system voltage. 550 ohms may not be enough for a 14v supply, puts current above 20mA across the LED. At 12v a 1K resistor is ~10mA, 2K = ~5mA. Option B supply the LED thru a voltage divider.