You can check the operation of the sending units for fuel and temp by
checkin the resistance, measured in ohms with a voltmeter.  The values for
the temp gauge are below.  The values for the gas gauge are on gerry
somewhere in the technical section.  If the senders are working properly
you can check the gauges by buying some resitors from radio shack and
"faking" the signal to the gagues.  Good luck and here is the temp sensor
data:
32 F    5,000-6,500 Ohms
68 F    2,000-3,000 Ohms
104F    1,000-1,500 Ohms
140F    500-675 Ohms
176F    275-375 Ohms
212F    150-250 Ohms

Andrew Fox
www2.hawaii.edu/~andrewf/vanagon/links.htm

On Wed, 26 Sep 2001, Hans Roos wrote:

> I've got an 89 Syncro and the fuel and temp gauges both work but they do
> not give accurate readings.  I have already checked & replaced the voltage
> regulator for the gauges but that made no difference.  Here is what is
> occurring:
>
> Fuel Gauge - Fill the tank and it reads full, as I drive it falls very
> quickly, after about 100 miles (which takes about 1/2 a tank) it reads dead
> empty, filling it up starts the process all over again.  When the problem
> first started it was only intermittent - now it happens all of the time.
>
> Temp Gauge - It simply reads to low.  It used to read just fine but now it
> barely gets off of the bottom white square.  I know the temps are higher
> than this as the cooling fan kicks in.  I have replaced the sender - no
> change :-(
>
> I do not think the inaccuracy of the gauges is caused by the same problem
> as the problems started happening many months apart but I've been wrong
> before!  Any suggestions or ideas?
>
> -Hans
>