Date:         Sat, 5 Jul 2008 21:57:11 -0500
Reply-To:     Stephen Edwards <welfarewrkr@IGC.ORG>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Stephen Edwards <welfarewrkr@IGC.ORG>
Subject:      Re: Purpose of "Voltage Stabilizer" in Instrument cluster?
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

Hi all.

Mark Drillock's explanation makes me wonder if this is related to the
problem I'm having.

I have a Vanaru conversion which was done about two years ago.  Since
the first winter I've had a problem - used to be intermittent, now
extremely frequent - with the coolant LED coming on when the coolant
level was not low, and the temp not particularly high.

Recently I noticed that it is most likely to happen when the
headlights are on - and almost 100% likely when the lights are on
high beam.

Sounds like I should check the voltage regulator - exactly where is
the little bugger and what does it look like?

TIA

Steve, 91 GL with 1995 Subie 2.2.


> Date:    Sat, 5 Jul 2008 12:18:04 -0700
> From:    neil N <musomuso@GMAIL.COM>
> Subject: Purpose of "Voltage Stabilizer" in Instrument cluster?
>
> Hi all.
>
> Does the voltage stabilizer work in conjunction with the engine
> coolant temp gauge?
>
> i.e. if one took the engine temp gauge out of the cluster, connected
> it straight to the temp sending unit (sensor) and 12+, would this give
> an innacurate reading of engine coolant temp?
>
> Like maybe too high?
>
> Thanks much!
>
> Neil.
>
>
> --
> Neil Nicholson '81 JettaWesty "Jaco
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-
> gas-engines
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>
> ------------------------------
>
> Date:    Sat, 5 Jul 2008 12:33:21 -0700
> From:    mdrillock <mdrillock@COX.NET>
> Subject: Re: Purpose of "Voltage Stabilizer" in Instrument cluster?
>
> The name is misleading perhaps. What it is really is a 10 volt
> regulator. It takes the varying 11-14 volts of the vehicle wiring and
> drops it down to a steady 10 volts. The vehicle wiring voltage varies
> depending on alternator output, what loads are turned on, etc. The
> "voltage stabilizer" provides the temp gauge and fuel gauge with a
> constant voltage no matter what else is going on so these gauges read
> the same no matter what else is going on. For example, otherwise when
> the radiator fan came on the gauge needles would move to different
> positions and then back again after the fan stopped. Headlights,
> wipers,
> etc would have similar effects.
>
> In other words the temp and fuel gauges are calibrated to run on 10
> volts, not 12 volts, and this component provides a stable 10 volts.
>
> Mark
>
>
>
> neil N wrote:
> Hi all.
>
> Does the voltage stabilizer work in conjunction with the engine
> coolant temp gauge?
>
> i.e. if one took the engine temp gauge out of the cluster, connected
> it straight to the temp sending unit (sensor) and 12+, would this give
> an innacurate reading of engine coolant temp?
>
> Like maybe too high?
>
> Thanks much!
>
> Neil.
>
>
> --
> Neil Nicholson '81 JettaWesty "Jaco
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-
> gas-engines
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>
>
>
> ------------------------------
>
> Date:    Sat, 5 Jul 2008 15:55:35 -0400
> From:    Mike S <mikes@FLATSURFACE.COM>
> Subject: Re: Purpose of "Voltage Stabilizer" in Instrument cluster?
>
> At 03:18 PM 7/5/2008, neil N wrote...
> Hi all.
>
> Hi Neil.
>
> Does the voltage stabilizer work in conjunction with the engine
> coolant temp gauge?
>
> Yes, it provides a constant 10 volts for the gauges.
>
> i.e. if one took the engine temp gauge out of the cluster, connected
> it straight to the temp sending unit (sensor) and 12+, would this give
> an innacurate reading of engine coolant temp?
>
> Yes.
>
> Like maybe too high?
>
> Yes.
>
> The gauges are bimetallic - they work by heating a special piece of
> metal which bends as it gets warm. There's a heating coil wrapped
> around tha piece of metal. 10 volts from the regulator goes to one end
> of the heating coil, the other is connected to the sensor (fuel,
> temp).
> The sensors offer a variable resistance. Less resistance causes more
> current to flow, making more heat, bending the metal more, making the
> gauge read higher.
>
> If you bypass the regulator, then you have 12 volts on one end of the
> heater, so more current will flow than is intended, and the gauge will
> read higher than it should.
>