Date:         Fri, 15 Apr 2011 17:40:25 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: What's the connection between the temp and fuel gauges?
Comments: To: David White <sirgrumpsalot@GMAIL.COM>
In-Reply-To:  <BANLkTikhARE7ZWPLAtX9MYOPHwOyvtNWOg@mail.gmail.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 03:49 PM 4/15/2011, David White wrote:
>Driving down the road, in the rain, both the coolant temp gauge and
>fuel tank gauge go to zero.

Both gauges are supplied with +10v from the voltage regulator on the
panel, so if there's a problem with it or its wiring the gauges will
stop.  The regulator gets +12v along with the rest of the panel so
any wiring problem is on the flexible circuit at or near the
regulator itself (see 90.4 figure 2).  Be gentle with the flexible
circuit, especially if it's a hot-weather vehicle - some of them are
delaminating.

>start the engine the coolant temp light  blinks forever but it's
>pretty faint.  When I start the engine sometimes the coolant blinks
>for the three seconds, other times it never blinks. The rest of the
>lights on the dash are bright. What's the deal? 1984 Vanagon GL

Get the voltage within spec and then revisit the LED blinker.  Proper
operation is 2-3 second blink at key-on.  If voltage is correct (10
+/- 0.5v) and you get extended blinking, very high probability you
need to replace or have replaced a 10 uF 16v capacitor inside the
temp gauge which controls blink duration.  Blink brightness (assuming
input voltage ok) is the LED itself.  Replacing it is quite possible
but not completely straightforward as it's a self-blinking LED that
runs on 5.0 volts, not a standard one like the rest of the panel
LEDs.  We can talk about that after you get the gauges reading correctly.

Yrs,
d