How to test temperature sender?

[pointynoggin]

Just put my rebuild in but the temperature gauge won't read.  Anyone know the testing procedure?

[maxfax]

That has the 2 pin plug for the temp gauge IIRC.. Brown wire and a yellow red I think..  Disconnect the sensor, turn the key on, jump those 2 pins, the gauge should fly up to hot..  If it does the sender is bad, if not it's wiring or the gauge...  If it turns out to be wires, the brown is a ground, the other is the signal to the gauge...

[pointynoggin]

Thanks,

I was hesitant to short the sender out in case of high current flow that would burn out the gauge.  I've done dumb stuff like that before and I have had to redo many things I have done to this car as it is.

Would you know the resistance range of the sender?  I may have a pot around I could use to test.

[maxfax]

Understood..  Been there, left the smoke outta stuff myself..       You'll be fine to short the gauge for testing purposes..  I don't know about driving 100K with it like that though..   

As far as a resistance spec for the sensor, that's been asked before, and seems to be a deep dark VW secret as of yet...  There is actually a special tool (vw 1301 ?) for testing the gauge..  I did some crude testing on a MK1 temp sensor (which should still operate in a similar range).. Results can be found in this post http://www.vwdiesel.net/forum/index.php?topic=28638.0

[pointynoggin]

Thanks, that is exactly what I needed!  Range~ open to 50ohms or so.

[smutts]

On the Mk2, the temp sender for the gauge is the same as for the glow plug controller, they are right next to each other. Swap the plugs and if the guage works and the glowplugs dont, you know it's the sender.

[pointynoggin]

test worked.  I found the gauge read from the side mounted sensor so I replaced the bad one.

Thanks!