[Gmecm] Shift light

[Robin Handley]

Thanks all.

I tried putting a dash warning light between A12 and battery +ve and, whilst
it didn't come on below my desired RPM, it didn't come on above it either. I
was wondering if my lack of VSS might stuff me. I haven't checked out the
code, yet, just assumed that GM would be sensible enough to enable the light
come what may, for safety... I'll switch to looking at this part of the
code...

I'm now wondering what the difference is between A12 ('upshift light') and
C13 ('one to four light'). (I've never  had access to any of the vehicles
normally fitted with GMECMs.)

Based on the name 'upshift light', I had thought that A12 just comes on when
the RPM is above the value set in $013E - i.e. an alert to the driver to
change up, and very useful to have. Is this not how it works? I can't
imagine what C13 does. Can somebody help? :-)

Robin

----- Original Message -----
From: <davesnothereman at netscape.net>
To: <gmecm at diy-efi.org>
Sent: 24 June 2006 17:06
Subject: RE: [Gmecm] Shift light


> "Robin Handley" <Robin at FuryWorld.fsnet.co.uk> wrote:
>
> >Anybody played with the shift light (pin A12) in a '727
> How 'bout a 7730?
>
> or its equivalent in
> >a '749?
> Yyyep.
>
> >
> >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.
> ... when the light is connected to battery power.
>
> >Is this
> >right? Same deal for the injector pins?
> When the injectors are connected to ignition power.
>
> >
> >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?
> Use a test light from power to the pin.  Much more dramatic and effective.
Check all variables for shift light.  Some may not do what they seem based
on labels.  VSS may be needed (vehicle moving bit may need to be set).
>
> Can send 7749 code with working shift light (on at WOT and 6300 ish rpm).
>
> Zaphod
> >
> >Robin
> >
> >_______________________________________________
> >Gmecm mailing list
> >Gmecm at diy-efi.org
> >http://lists.diy-efi.org/mailman/listinfo/gmecm
> >
>
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