1999 jetta gls 2.8l need help
 

hey i just bought this jetta and noticed that the temp gauge doesnt move at all, what usually causes this on this car? thanks in advance
i also have a C.E.L which i havent pulled the code on yet

Welcome to the forum. Attachment 3295

Well the temperature gauge works of an engine thermistor (coolant temperature sensor) its resistance varies with temperature. You could remove it from the engine and put it in a sausepan of water with a thermometer inserted. Then you need an multimeter to measure the resistance at various temperatures. Now I don't have the specific values for that engine but the resistance should come down with an increase in temperature. In the olden days you could bridge bother wires in the connector with a paper clip then the igition on and the coolant temperature gauge swings over the hot so the gauge is working ok. I'm not sure if these computer controlled system will allow that.

You could always buy a new coolant temperature sensor if you can't test it. The other thing is it could be the thermostat that has stuck open. You could remove that from the engine and test that in a similar manor but you don't need a multimeter the opening temperature should be marked on the thermostat. make sure the valve is fully closed before boiling it. If in doubt replace the thermostat.