Date: Sun, 3 May 2015 23:06:54 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: Wonky temp gauge
In-Reply-To: <BLU437-SMTP1041BC12483705B86005C64B8D30@phx.gbl>
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At 06:21 PM 5/3/2015, Jeff Palmer wrote:
>Latest update: wiggling the foil/wire harness behind the tach
>results in the red glowing light to begin flashing. Not sure if it
>would stay on or off if I held onto it long enough.
Jeff, you obviously have contact problems of some sort with the
flexible circuit. Pull the panel and trace out the connections with
your meter, find out where the problem(s) are. I'll hazard a guess
that your blinker issue is because of a bad ground. You have to get
to the point where you have a gauge that blinks for 2-3 seconds every
time you turn the power on, and with the coolant level controller
unplugged and the gauge sender unplugged the gauge does not rise but
sits permanently off the cold end. Until you have that, there's no
point worrying about the rest of the system.
Once you get to that point you add the gauge sender back in and see
if it's behaving how it should. It should read correctly, and if you
momentarily short the gauge sender line to ground the light should
blink for a couple seconds after you remove the short. Don't short
it to ground longer than say 15-20 seconds, it's not meant to run that way.
And once the gauge is working properly for temperature, and reliably
blinking for a couple seconds at turn-on, then you can add the
coolant level controller back in and see whether it's behaving
(hopefully you'll have found a new-type controller to use instead of
the original one, but the same applies either way. With the level
sender unplugged it should cause the gauge to start blinking a few
seconds after you turn the key on, but after the initial power-on
blink has stopped. With the level sender plug jumpered from pin to
pin the light should stay off after the initial blinks. If it simply
starts blinking at turn-on and doesn't stop, the controller is bad,
if the tests up to this point are correct.
Once you have it working correctly with the sender plug open and
jumpered, plug it into the sender. If it now blinks when it
shouldn't, pull the sender and clean the pins with green Scotch-Brite
until they're shiny-bright. If still no good, either the connector
isn't making good contact with the sender, or your coolant mix is too weak.
>Is there nothing common that would cause both to malfunction at the same time?
Not as such. The gauge itself has nothing electronic, it's just a
heater. Show it a low resistance to ground on the sender terminal
and it gets hotter and the needle goes up. Any time the needle
reaches the red zone the blinker should be blinking as well, and the
blinker must always blink for a couple seconds when you give the
gauge power. So an open circuit on the guage power could cause the
blinker to not work, but then the gauge could not rise. OPen circuit
on the gauge ground will stop the blink and will not prevent the
gauge from rising, but it cannot cause the gauge to rise.
Yrs,
d
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