Running a direct yellow wire from sender to the blue gauge wire at the
cluster.  Direct ground from engine to gauge wire (blk).  Purple gauge wire
to a lead to the dimmer switch and power (red) from dash.

In every scenario the gauge spikes - unless I ground the sender separately
- and the gauge does not zero out with the sender wire disconnected -
unless the sender is grounded separately.

Bruce

On Thu, Jun 24, 2021 at 11:28 AM Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> Maybe sensor and ground wire on gauge swapped or gauge ground open.
> Sometimes the markings are confusing.
>
>
>
> Dennis
>
>
>
>
>
> *From:* Bruce Todd <beeceetee@gmail.com>
> *Sent:* Thursday, June 24, 2021 2:18 PM
> *To:* Dennis Haynes <d23haynes57@hotmail.com>
> *Subject:* Re: Oil Temp Sender and Gauge
>
>
>
> Doesn’t appear I can do those things.  Gauge wire not connected to sensor
> - temp spikes.  Grounding the sensor wire and gauge falls to 0.
>
>
>
> Faulty gauge perhaps?
>
>
>
> BT
>
> On Thursday, June 24, 2021, Dennis Haynes <d23haynes57@hotmail.com> wrote:
>
> Take another look that you do not have one of the gauge wires swapped.
> Generally these gauges use reverse temp coefficient sensors, resistance
> goes down as temp goes up. Not connected to the sensor, powered on the
> gauge needle should not move. Ground the sensor wire and it should peg. If
> you can't do those 2 steps the sensor and added ground will not help. If
> the engine is grounded enough to let the starter start it and the
> alternator charge the battery the gauge should work.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Bruce
> Todd
> Sent: Thursday, June 24, 2021 11:56 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Oil Temp Sender and Gauge
>
> I think I might have an answer - I will try grounding the sender on the
> body of the sender - and not directly where the sender wire is also
> attached.
>
> BT
>
> On Thu, Jun 24, 2021 at 8:53 AM Bruce Todd <beeceetee@gmail.com> wrote:
>
> >
> > So - I am having some issues getting an aftermarket digital oil temp
> > gauge to work.
> >
> > The sender connects to a threaded adaptor that replaces the oil relief
> > plug - which I imagine many of you folks likely have in place on your
> > beloved vans.  First question - if this is your set up, have you had
> > to ground the sender since the bottom of the block is aluminum?  When
> > I jumper a ground to the sender the gauge reads -18C which equates to
> > 0 Fahrenheit...(I opted for Celcius over Fahrenheit).  Without the
> > jumper to the ground, the gauge reads full scale - 181C or 300 F.
> > Note - This is just with the ignition on without any temp being
> generated from the motor.
> >
> > When I run the motor with the sender jumped to ground and the sender
> > wire attached to the gauge the gauge just stays on -18C and there is
> > no fluctuation - so somewhere in this equation the resistance isn't
> > dropping as the oil temp rises....which is how I believe things work
> > with temp gauges.
> >
> > If I drive the van without the sender grounded - the gauge at full
> > scale
> > (181C)  begins to slowly decrease as the motor warms up - but
> > continues to drop until it reaches -18C and then stays there - it
> > doesn't set on a temperature.
> >
> > This gauge is from Intellitronix (M9108) and came with a sender.  I
> > had originally installed a GW sender but then exchanged that earlier
> > this week thinking it might be the issue as it may not be matched
> > correctly with the gauge.
> >
> > When looking at GW (as a resource) they don't seem to mention
> > grounding the sender - nor did the instructions I received for the
> > gauge and sender - however I imagine they typically sell these units
> > to vehicles that don't have an aluminum cases and the sender grounds
> directly to the motor.
> >
> > Any thoughts appreciated as I am running out of ideas here.
> >
> >
> > Bruce
> >
>
>