Temperature gauage not workin!

[Davignon]

Hey guys,
Just noticed today that my temperature gauge stopped working, doesnt move at all off 0, just wondering where i should start to trouble shoot? Btw just incase anyone asks, its not the digital one, the one on the far left of the dash. Had the water pump replaced a little while back if its relevent, and also had a look on the web and couldnt find much, hence why posting here. Any help is appreciated Thank you!

[mattross]

If you have a voltmeter ,Try the sender, 4 pin on top of the coolant flange near head of car. Are you radiator fans working?

[The_Hawk]

Here is an image of the 4banger sensors mattross is talking about:



When I had issues with my thermo fans I did a pile of research on the temperature sensors in the VR6. There are three (maybe even four) temperature sensors in the VR6. Each does something different and from memory the one that does the gauge is pretty much only for the gauge. Some mounter here, one on the radiator... don't recall if there any more else where

[Davignon]

Righto thanks heaps guys, will grab myself a gauge and check it out! thanks again

[mattross]

Bentley Publishers - Technical Discussions : vw jetta mk3 coolant temp sensor ...

Testing Some Engine Sensors
Coolant Temp Sensors -
CTS is easy to test. Also known as an ECT (common name).
Anyhow, turn car on.
Backprobe sensor with bent safety pins.
Set DVOM to read Volts DC (0-20 V scale)
Use this ASE chart as a guide.

This is a better test than using OHMs..
Testing the TPS
Most TPSs are 3 wire potentiometers Potentiometer - Wikipedia, the free encyclopedia
Testing a TPS is fairly easy. Step 1 - get a DVOM and some safety pins and jumper wires.
Step 2 - Locate TPS
Turn car "on" (but do not start), set meter to read DC volts (0-20 volts, this system works on 0-5 volts.)
Bend open the safety pins, and carefully slide the pins past the wires into the weatherpack harness on the TPS. Use the jumper wires and attatch them to the DVOM.
Backprobe the two outer wires of the TPS. You should get almost dead 5 volts.

Next, move one outer wire to the inner wire. You should either be reading .5 OR 4.5 volts depending on what part of the CKT you are on.
Slowly rotate the TPS through its entire arc. The voltage should slowly go up (without glitches) as you turn it. If you start at .5 Volts, it should climb to 4.5 at Wide Open Throttle (WOT). If you start at 4.5, the voltage should drop to .5.
If this happens, your TPS is working. If you get glitches, or the voltage drops to 0 or jumps to 5v then its bad (worn out..)
This same test can be done with the harness disconnected, and testing for Ohms, but voltage testing is better as it stresses the CKT some..
More than you ever wanted to know:
This should work on most TPSs out there, however just make sure you probe the right wires on the OBD II models as there is more to the TB then the OBD I cars..
Leave everything plugged in, and make sure the car is on.
If voltage is out of range, good chance sensor is bad.

[mattross]

Also maybe use dan reeds page,
A/C MKIII Page

[Davignon]

Legend Matross, will get onto it ASAP, time is tight atm, but so glad there are some fellas on here willing to give some time to help out!