[Gmecm] Re: Gmecm Digest, Vol 16, Issue 26

[William Lucke]

There should be a pull-down resistor on the pin. Your meter will tell 
you it's grounded unless there's a measurable current flowing.



Will


> From: "Robin Handley" <Robin at FuryWorld.fsnet.co.uk>
> Subject: [Gmecm] Shift light
> 
> Anybody played with the shift light (pin A12) in a '727 or its equivalent in
> a '749?
> 
> Going by the circuit diagram for a '727, ignition volts are supplied to the
> non-ECM side of the shift light. My limited electrical knowledge tells me
> that the ECM ground this pin when it wants the light to come on. So, when it
> wants the light to be off, the pin should be at battery voltage. Is this
> right? Same deal for the injector pins?
> 
> Could be my minimalist installation causing bypasses in logic (although
> can't see why), but I see no voltage on the shift light pin, whether the RPM
> is below the light on threshold or not. Am I missing something?
> 
> Robin