DSP 5 switch question

[andrewjamesbond1]

Looking for some help on DSP Switch wiring.

Is the ECM the voltage or current source in the DSP Circuit? Where does the computer read the voltage? Can too much amperage do harm to the computer?

Any help would be appreciated and preferrably Ross could chime in :)

Thanks!

Andrew

[Dmaxink]

the ecm emits 5v to the switch, and the switch limits the voltage from 1-5 is my understanding...I'm sure someone else could be more specific..

[Ira]

It's a input for an oil pressure sender or the like. One side of the switch is grounded, the other connects to the ecm through an input that look like a pull up resistor to 5V.

Unconnected that pin measures 5V or so, grounded it measures 0V. The various resistances of the DSP5 switch drop the voltage from 5V down to 1V in 1V or so steps.

Unless you connect 12V to the switch you can't cause any harm to the ECM, and even then it might be protected.

Ira

[andrewjamesbond1]

So does the ground pin on the ECM since the voltage? That's where I am stuck and think the ECM is a current source and the ECM senses the voltage before the switch... Could be wrong? :shock:

[andrewjamesbond1]

So then theoretically you can run as much current thru the DSP switch and be fine because the ECM is supplying the current?

[andrewjamesbond1]

I am going somewhere with this. Come December, I will have a little goody for you guys :D

[andrewjamesbond1]

Ross, if you are out there, do you have any insight?