[Gmecm] MIL wiring (Newbie Question)

[Scott Peitzsch]

> This is a fairly easy question, I think.  What is the standard wiring for 
> the MIL output  to
> the lamp?  I have put a voltmeter on it and it seems to go high (WRT GND) 
> when the lamp
> should be off and low when the lamp should be on.  This is actually a MEFI 
> 4 controller,
> but it is a Delphi/DELCO product and shares much of the same architecture 
> and features
> as it's automotive cousins.  Is this output actually a switching ground 
> i.e., should my MIL
> have 12V+  on one side with the other (GND) tied to this "output"?


You're pretty much nailed it - typical GM MIL wiring is +12VDC to one side 
of the
lamp with the ECM/PCM switching the other side to ground when active.

-Scott