Thanks for all the input, however some of you are not really understanding the problem.  The light DOES NOT BLINK, it comes on steady.  This is what is odd.  I have checked the terminals to the level sender in the tank and the sender, both are good.  If I connect the terminals together the lights blinks as it should.  Being on steady is what the mystery is.  I also notice that if I let the van idle for a long time, 1/2 hour or more the light does not come on until the engine is revved up past 2000 RPM.  This phenomene  started all of a sudden, no intervention to anything on the engine had been done previously.  Coolant mixture is as it has always been previously to this happening.  

Frank

> On Sep 18, 2022, at 12:00 AM, Automatic digest processor <LISTSERV@GERRY.VANAGON.COM> wrote:
> 
> There is one message totalling 179 lines in this issue.
> 
> Topics of the day:
> 
> 1. Coolant light mystery
> 
> ----------------------------------------------------------------------
> 
> Date:    Sat, 17 Sep 2022 11:30:55 -0600
> From:    OlRivrRat <OlRivrRat@COMCAST.NET>
> Subject: Re: Coolant light mystery
> 
>       I was able to find that info in the TSB & I=E2=80=99m not sure =
> why they say that Resistances
> 
> are required unless maybe that pertains to the part of that circuit that =
> causes the light to
> 
> flash when the Temp Rises into the OverHeat Range ~
> 
>       I contend that it is just a simple switch due to fact that if, =
> with Igni'Key On,
> 
> you unplug the Sensors connector the light will Come On/Flash & if you =
> then put
> 
> a jumper wire across the 2 connections in the connector, turn Igni,Key =
> Off & On,
> 
> & if the rest of the Circuit is functioning correctly, ie No Opens, the =
> light will go
> 
> Off > No Resistances Required ~
> 
> 
> 
>> On 16 Sep , 2022, at 11:25 AM, Ed McLean <email99@NC.RR.COM> wrote:
>> =20
>> Please check the following Vanagon Technical Service Bulletin clip =
> where it
>> states the resistance, checked with a digital multimeter, must be =
> between
>> 31K Ohm and 65K Ohm and the coolant concentration must be below 60 =
> percent
>> for proper Coolant Indicator LED operation.
>> =20
>> =20
>> =20
>> https://beakerbus.nl/2016/vw-vanagon-technical-service-bulletins/
>> =20
>> =20
>> Technical Bulletin
>> Group:    90
>> Number:   92-03
>> Date:     February 29, 1992
>> Subject:  Coolant Indicator LED is Flashing at Normal Temperatures
>> Model(s): All Models
>> =20
>> =20
>> =20
>> * refer to appropriate wiring diagram
>> * disconnect coolant level sensor electrical connector
>> * check coolant level in coolant reservoir
>> *** MUST be between MIN and MAX marks
>> * set digital multimeter, Fluke 83 (US 1119) to ohms function
>> * check resistance of level sensor with digital multimeter Fluke 83
>> (US 1119)
>> *** must be between 31K Ohm and 65K Ohm with correct COOLANT LEVEL
>>    AND COOLANT CONCENTRATION.
>> =20
>> NOTE
>> If coolant resistance is NOT within the above specifications, the
>> coolant MUST be drained and replaced with NEW coolant mixture of
>> 50 percent water and 50 percent phosphate free coolant antifreeze,
>> Part No. ZVW 237 104.  (In Canada, use Part No. G 001 100).  The
>> mixing should be performed before filling vehicle cooling system.
>> =20
>> *****************************************************************
>> * CAUTION                                                       *
>> * Coolant concentrations of 60 percent or higher will cause the *
>> * overtemp / low coolant LED to activate.                       *
>> =20
>> End
>> =20
>> =20
>> =20
>> =20
>> On Fri, 16 Sep 2022 10:35:38 -0600, OlRivrRat <OlRivrRat@COMCAST.NET> =
> wrote:
>> =20
>>>     Pretty darn sure that that Coolant Level Probe in the Expansion
>> Tank
>>> =20
>>> is nothing more sophisticated than a simple Switch > When the Probes =
> are
>>> =20
>>> Submerged > Circuit Closed,, When Coolant Level drops below Probes =
> the
>>> =20
>>> Circuit Opens ~ Any Break in the Circuit will cause the Light to come =
> on ~
>>> =20
>>> There are some Electronic Components within the Circuit that can =
> cause the
>>> =20
>>> light to have some odd behaviors @ times ~ I have seen, in several
>> different
>>> =20
>>> Vanagons, a condition where if the Igni=C3=A2=C2=80=C2=99Key was =
> turned to Start in a
>> normal
>>> =20
>>> way (1 continuous move from Off to On to Start) the Light would Stay =
> Lit
>>> =20
>>> but if the Igni=C3=A2=C2=80=C2=99Key was turned to On & left in that =
> position for 10-15
>> Sec=C3=A2=C2=80=C2=99s
>>> =20
>>> before turning to Start then the Light would go Off & act normally ~
>>> =20
>>> I suspect that D Beierl or Dennis H or others may have an explanation =
> for
>>> =20
>>> that condition ~
>>> =20
>>> =20
>>> =20
>>>> On 16 Sep , 2022, at 9:33 AM, Ed <email99@NC.RR.COM> wrote:
>>>> =20
>>>> I believe the coolant light circuit measures resistance between the =
> two
>> pins
>>>> of the sensor in the plastic tank.  If the resistance is out of =
> range
>> then
>>>> the light will come on.  If the coolant is low or sloshes away from =
> the
>>>> sensor pins then the light will come on.  If the coolant has too =
> much
>>>> antifreeze then the resistance between the pins will be out of spec =
> and
>> the
>>>> light will come on.  If the pins are dirty or corroded then they =
> might
>> read
>>>> incorrect resistance.  There could also be a fault in the wiring for =
> the
>>>> light that could cause the light to come on.  I don't know how to =
> test
>> the
>>>> sensor.
>>>> =20
>>>> That all I have.
>>>> =20
>>>> =20
>>>> =20
>>>> On Fri, 16 Sep 2022 05:57:37 -0700, David McNeely
>> <davmcneely40@GMAIL.COM>
>>>> wrote:
>>>> =20
>>>>> Doesn't the coolant light indicate the level of coolant, not the
>>>>> temperature?  I have actually had it come on when I hit a rough =
> spot in
>> the
>>>>> road, back some years ago.  Bouncy, bouncy, and the light blinked =
> on and
>>>>> off.
>>>>> =20
>>>>> On Fri, Sep 16, 2022 at 5:16 AM Ed McLean <email99@nc.rr.com> =
> wrote:
>>>>> =20
>>>>>> The original note was a short question asking why the coolant =
> light
>> would
>>>>>> turn
>>>>>> on and off at random times for no apparent reason while the =
> temperature
>>>>>> gauge
>>>>>> remained in the normal range.
>>>>>> =20
> 
> ------------------------------
> 
> End of vanagon Digest - 16 Sep 2022 to 17 Sep 2022 (#2022-210)
> **************************************************************