thanks Mark,
another extremely informed and intelligent email I'll file away for future
reference !
Scott
----- Original Message -----
From: "mark drillock" <mdrillock@COX.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, July 06, 2010 5:45 PM
Subject: Re: adding resister to center 1.9 coolant temp gauge?

> Be careful. Adding a resistor to "normalize" the reading has pitfalls.
> I'm curious why you presume that the sender that in your words died was
> reading correctly until then. In any case, a 10 ohm resistor would be
> what I would try if I simply had to. Much more than that will prevent
> the temp warning light from working right. If I were you I would test
> the gauge and gauge wiring with some various resistor values first to
> determine if the sender is the problem with the high reading. Here is
> what I have come to expect.
>
> 33 ohms  = HOT!!! and FLASHING led
> 50 ohms  = hot but not flashing
> 67 ohms  = just above the led
> 100 ohms  = at or just below the led
> 200 ohms = above cold
>
> Buy a 5 pack of 100 ohm 1/4W resistors from RadioShack for about $1.
> Combine them in various ways to get each of the above values.
>
> 3 in parallel = 33 ohms
> 2 in parallel = 50 ohms
> 1 in parallel with 2 in series = 67 ohms
> 1 by itself  = 100 ohms
> 2 in series  = 200 ohms
>
>
> Mark
>
> Paul Guzyk wrote:
>> My 1.9 style dash coolant temp sender died.
>>
>> I replaced it with a new one.   Now the gauge reads high, about 65%-70%
>> when normal operating temperature instead of 50% (LED dead center) like
>> the old one.
>>
>> I'm thinking of adding a resister in series with the new temp sensor to
>> get the needle back in the middle.
>>
>> Anyone seen this before?
>> What value resister/pot did you add?
>>